Image recording apparatus for transporting photosensitive film sheet

A transport mechanism for transporting a photosensitive film sheet for use in an image recording apparatus, including an auxiliary scanning drum, a nip roller held in contact with the auxiliary scanning drum, a support plate extending substantially horizontally in a sheet transport path, a push lever provided at one end of the support plate and a stopper provided at the other end of the support plate.

BACKGROUND OF THE INVENTION 
The present invention generally relates to image recording apparatuses and 
more particularly, to a transport mechanism for transporting 
photosensitive film sheets for use in an image recording apparatus of a 
laser beam type in which images are formed on the photosensitive film 
sheets by using laser beams. 
Conventionally, there has been proposed for example, an image recording 
apparatus of this kind as shown in FIG. 1. The known apparatus includes a 
magazine 1 having photosensitive film sheets S stacked thereon, a suction 
means 2, a pair of nip rollers 3, an auxiliary scanning drum 4, a pair of 
nip rollers 5, a stopper 6 and a laser beam unit 7. The film sheets S are 
taken up from the magazine 1 one sheet at a time by the suction means 2 so 
as to fall down between the auxiliary scanning drum 4 and the nip rollers 
5 through the nip rollers 3. Then, the stopper 6 is retracted from the 
auxiliary scanning drum 4 and, at the same time, the nip rollers 5 are 
brought into pressing contact with the auxiliary scanning drum 4 through 
the fallen film sheet S. Thus, when the film sheet S is being transported 
downwardly by a rotational force of the auxiliary scanning drum 4 which is 
rotated at all times, scanning of the laser beams is performed on the film 
sheet S by using laser beams irradiated from the laser beam unit 7 and 
thus, the images are formed on the film sheet S. Meanwhile, in sheet 
transport mechanisms for use in image recording apparatuses of this kind, 
in order to eliminate inaccurate scanning employing laser beams, it is 
generally necessary to eliminate unstable transport of the film sheet and 
transport the film sheet by positioning the film sheet accurately. 
However, in the known apparatus of FIG. 1, since it is so arranged that 
the film sheets S fall down by their own weight, it is difficult to 
accurately position the film sheets S due to variations in weight of the 
film sheets S or deflection of the film sheets S. Furthermore, in the 
known apparatus, the auxiliary scanning drum 4 is continuously rotated so 
as to prevent irregular rotation of the auxiliary scanning drum 4. 
However, since the nip rollers 5 are brought into and out of contact with 
the auxiliary scanning drum 4, torque of the drum 4 varies at the time of 
pressing contact of the nip rollers 5 with the drum 4, so that irregular 
rotation of the drum 4 takes place, thereby resulting in unstable 
transport of the film sheets S. Since even minute instability of transport 
of the film sheets S strongly affects reproducibility of the images in the 
case where an original having continuous tone, e.g., an X-ray film is 
reproduced, it is highly important to eliminate unstable transport of the 
film sheets S. 
SUMMARY OF THE INVENTION 
Accordingly, an essential object of the present invention is to provide an 
improved transport mechanism for transporting photosensitive film sheets 
for use in an image recording apparatus, in which the photosensitive film 
sheets can be transported onto an auxiliary scanning drum after having 
been positioned accurately and unstable transport of the photosensitive 
film sheets on the auxiliary scanning drum does not take place, with 
substantial elimination of the disadvantages inherent in conventional 
transport mechanisms of this kind. 
In accomplishing these and other objects according to one preferred 
embodiment of the present invention, there is provided an improved 
transport mechanism for transporting a photosensitive film sheet for use 
in an image recording apparatus including a supply means for supplying 
said photosensitive film sheet to said transport mechanism, said transport 
mechanism comprising: an auxiliary scanning drum which is continuously 
rotated at a constant speed; said image recording apparatus effecting, by 
using laser beams, main scanning of image signals on said photosensitive 
film sheet which is being transported on said auxiliary scanning drum at 
the constant speed; a nip roller which is at all times brought into 
contact with said auxiliary scanning drum so as to be rotated by said 
auxiliary scanning drum; a support plate which is substantially 
horizontally provided in a sheet transport path so as to extend from said 
supply means to said auxiliary scanning drum such that said photosensitive 
film sheet is slidably moved on said support plate; a push lever which is 
provided at one end of said support plate adjacent to said supply means so 
as to be projected into and retracted away from said sheet transport path 
such that said push lever urges forwardly a trailing edge of said 
photosensitive film sheet when said push lever is projected into said 
sheet transport path; and a stopper which is provided at the other end of 
said support plate adjacent to said auxiliary scanning drum so as to be 
projected into and retracted away from said sheet transport path such that 
said stopper positions a leading edge of said photosensitive film sheet 
when said stopper is projected into said sheet transport path; said 
photosensitive film sheet supplied from said supply means onto said 
support plate being displaced by said push lever so as to to be positioned 
on said support plate through contact of said leading edge with said 
stopper when said push lever is initially projected into said sheet 
transport path; said photosensitive film sheet positioned on said support 
plate being displaced by said push lever so as to be gripped, at said 
leading edge, between said auxiliary scanning drum and said nip roller 
when said push lever is again projected into said sheet transport path. 
Namely, since the photosensitive film sheets are slid on the substantially 
horizontal support plate, there has been difficulty in accurately 
positioning the film sheets due to variations of weight of the film sheets 
or deflection of the film sheets. The film sheet, which is positioned 
accurately immediately before the auxiliary scanning drum by the stopper 
through contact of the stopper with the leading edge of the film sheet, is 
inserted, by an urging force of the push lever, between the auxiliary 
scanning drum and the nip roller both rotating continuously through 
contact therebetween. Accordingly, the film sheet is prevented from coming 
into contact with the stopper or the push lever when the film sheet is 
being transported by the auxiliary scanning drum. Thus, in accordance with 
the present invention, unstable transport of the film sheets does not take 
place through elimination of variations of load of the auxiliary scanning 
drum.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to the drawings, there is shown in FIG. 2, an image recording 
apparatus P in which a transport mechanism K for transporting 
photosensitive film sheets S, according to the present invention is 
incorporated. The film sheets S are stacked on one another in a supply 
cassette 10 such that photosensitive faces of the film sheets S are 
oriented upwardly. A suction pad 12 connected with an air cylinder 11 is 
pivotally provided above leading edges of the film sheets S so as to be 
pivoted about a shaft 13 upwardly and downwardly together with the air 
cylinder 11. When the suction pad 12 has been pivoted downwardly, the 
suction pad 12 sucks up the film sheets S through an air sucking operation 
of the air cylinder 11 so as to lift up an uppermost one of the film 
sheets S. Furthermore, a pair of feed rollers 14 are movably provided so 
as to be moved in the leftward and rightward directions in FIG. 2 at a 
height substantially equal to that of the leading edge of the film sheet S 
lifted up by the suction pad 12. 
The transport mechanism K generally includes a support plate 15, a push 
lever 16, a stopper 18, an auxiliary scanning drum 20 and a pair of nip 
rollers 21. In response to a transport start signal for starting transport 
of the film sheet S, the feed rollers 14 are moved in the rightward 
direction in FIG. 2 while being rotated and thus, grip therebetween the 
lifted film sheet S so as to feed the film sheet S onto the support plate 
15 immediately. It is to be noted that rotation of the feed rollers 14 is 
stopped at the time when the film sheet S has been fed onto the support 
plate 15. The above described stopping of rotation of the feed rollers 14 
is performed so as to prevent, so much as possible, unstable transport of 
the film sheet S due to its vibration resulting from drive of the feed 
rollers 14. The support plate 15 is horizontally provided in a sheet 
transport path so as to extend from the feed rollers 14 to the auxiliary 
scanning drum 20. The support plate 15 has a length slightly larger than 
that of the film sheet S and an upper face of the support plate 15 is so 
finished as to allow the film sheet S to slide thereon. The push lever 16 
is pivotally provided at one end of the support plate 15 adjacent to the 
feed rollers 14 and is pivoted about a shaft 17 so as to be projected into 
and retracted away from the sheet transport path. Meanwhile, the stopper 
18 is pivotally provided at the other end of the support plate 15 adjacent 
to the auxiliary scanning drum 20 and is pivoted about a shaft 19 so as to 
be projected into and retracted away from the sheet transport path. When 
the push lever 16 is pivoted in the clockwise direction in FIG. 2 so as to 
be projected into the sheet transport path, the push lever 16 urges the 
trailing edge of the film sheet S forwardly. The stopper 18 has a hooked 
end. When the stopper 18 is pivoted in the counterclockwise direction in 
FIG. 2 so as to be projected into the sheet transport path, the leading 
edge of the film sheet S is brought into contact with the hooked end of 
the stopper 18 and thus, the film sheet S is accurately positioned on the 
support plate 15 by the stopper 18. The film sheet S is finally pushed in 
the leftward direction in FIG. 2 by the push lever 16 so as to be gripped 
between the auxiliary scanning drum 20 and the nip rollers 21, which 
operation will be described in detail hereinbelow. 
The auxiliary scanning drum 20 is continuously rotated in the 
counterclockwise direction in FIG. 2 during a recording operation of the 
image recording apparatus P, while the nip rollers 21 are at all times 
brought into contact with the auxiliary scanning drum 20 so as to be 
rotated by the auxiliary scanning drum 20. As soon as the film sheet S is 
gripped between the auxiliary scanning drum 20 and the nip rollers 21, the 
film sheet S is transported in the leftward direction in FIG. 2 by a 
rotational force of the auxiliary scanning drum 20. 
The image recording apparatus P further includes a laser beam unit 22 
disposed above the support plate 15. The laser beam unit 22 includes a 
beam generator 23 and a reflecting mirror 24. Laser beams generated from 
the beam generator 23 are irradiated between the nip rollers 21 so as to 
perform main scanning on the photosensitive film sheet S transported on 
the auxiliary scanning drum 20 such that a predetermined image is formed 
on the film sheet S. The film sheet S, having the image thus formed 
thereon, is carried from between the auxiliary scanning drum 20 and the 
nip rollers 21 and then, falls down into a take-up cassette 25 by its own 
weight. In order to positively shield the film sheets S in the take-up 
cassette 25 from light, the take-up cassette 25 is provided with a light 
shielding cover which is so driven as to cover and uncover an opening of 
the take-up cassette 25 upon detection of transport of the film sheet S. 
Since the film sheets S accommodated in the take-up cassette 25 have been 
subjected to exposure only, the take-up cassette 25 containing the exposed 
film sheets S is taken out of the image recording apparatus P such that 
the exposed film sheets S are subsequently processed by a developing 
device and a fixing device. 
Hereinbelow, operations of the transport mechanism K will be described with 
reference to FIG. 3. Initially, when the film sheet S is being carried 
onto the support plate 15 by the feed rollers 14, the push lever 16 is 
upwardly retracted away from the sheet transport path and the stopper 18 
is projected into the sheet transport path as shown in FIG. 3a. Then, when 
the film sheet S has been carried onto the support plate 15 by the feed 
rollers 14 as shown in FIG. 3b, the push level 16 is pivoted in the 
clockwise direction so as to urge the trailing edge of the film sheet S 
forwardly as shown in FIG. 3c. At this time, the leading edge of the film 
sheet S is brought into contact with the stopper 18 and thus, a central 
portion of the film sheet S is deflected slightly upwardly by an urging 
force of the push level 16. Subsequently, the push lever 16 is pivoted in 
the counterclockwise direction so as to be retracted away from the 
trailing edge of the film sheet S as shown in FIG. 3d. Thus, the film 
sheet S is placed in a flat state on the support plate 15 and the leading 
edge of the film sheet S is accurately positioned by the stopper 18. 
Meanwhile, it is to be noted that the push lever 16 is required to be 
retracted away from the sheet transport path relatively slowly. Namely, in 
the case where the push lever 16 is retracted away from the sheet 
transport path rapidly, such an undesirable phenomenon takes place that 
the leading edge of the film sheet S is separated away from the stopper 18 
when the film sheet S deflected by the urging force of the push lever 16 
restores the flat state by its own elasticity. Thereafter, the stopper 18 
is pivoted in the clockwise direction so as to be retracted away from the 
sheet transport path as shown in FIG. 3e and then, the push lever 16 is 
again pivoted in the clockwise direction so as to push forwardly the 
trailing edge of the film sheet S as shown in FIG. 3f. Thus, since the 
film sheet S is slid on the support plate 15, the leading edge of the film 
sheet S is gripped between the rotating auxiliary scanning drum 20 and the 
rotating nip rollers 21 such that the film sheet S is subsequently 
transported by the rotational force of the auxiliary scanning drum 20. 
It should be noted that drive of the push lever 16 and the stopper 18 is 
controlled by a sequence circuit or a microcomputer through a combination 
of detection signals of the film sheet S and timers. These control devices 
are provided in a control cabinet 26 together with other control 
components. 
It should be further noted that the transport mechanism of the present 
invention can be modified in various ways. For example, it can also be 
arranged such that the push lever 16 and the stopper 18 are projected into 
the sheet transport path from below. 
As is clear from the foregoing description, in accordance with the present 
invention, since the photosensitive film sheet is slid on the 
substantially horizontal support plate, inaccurate positioning of the film 
sheets due to variations in weight of the film sheets or from deflection 
of the film sheets is avoided and the leading edge of the film sheet can 
be accurately positioned immediately before the auxiliary scanning drum 
through operative association of the push lever with the stopper. 
Furthermore, in accordance with the present invention, since the auxiliary 
scanning drum is at all times rotated continuously in contact with the nip 
rollers and the film sheet does not come into contact with the stopper, 
the push lever, etc. during transport of the film sheet on the auxiliary 
scanning drum, load of the auxiliary scanning drum does not vary and thus, 
unstable transport of the film sheets is eliminated, thereby producing 
images of high quality. 
Hereinbelow, a suction mechanism and a feed mechanism both employed in the 
image recording apparatus P will be described with reference to FIGS. 4 to 
11. Initially, the suction mechanism is described with reference to FIGS. 
4 to 7. In the suction mechanism, the supply cassette 10, which is 
sufficiently shielded from light, is so provided as to be drawn out of the 
image recording apparatus P. A plurality of the photosensitive film sheets 
S are placed on a retainer plate 32 in the supply cassette 10. The 
retainer plate 32 is raised, at one end thereof, by a spring 33 such that 
the uppermost one of the film sheets S is maintained at a predetermined 
height regardless of increase or decrease of the number of the film sheets 
S stacked on the retainer plate 32. In this embodiment, the suction 
mechanism includes four air cylinders 11 each having piston rod 42 and 
four suction pads 12 attached to lower faces of four holder plates 36, 
respectively. Four brackets 37 are, respectively, secured to the lower 
faces of the holder plates 36 and the holder plates 36 are pivotally 
mounted on the shaft 13 through the brackets 37. Namely, the four suction 
pads 12 are provided independently of each other in a widthwise direction 
of the sheet transport path so as to be pivoted about the shaft 13 
upwardly and downwardly. Each of the suction pads 12 is communicated, via 
an adaptor 39, with a chamber 41 (FIG. 8) of each air cylinder 11 provided 
on each holder plate 36. Meanwhile, one end of each piston rod 42, which 
is urged by a return spring (not shown) in the direction indicated by the 
arrow b in FIGS. 4 and 5, is coupled with a link means 43. 
The link means 43 includes four links 45 rotatably mounted on a shaft 44, 
four links 47 secured to a driving shaft 46, and four links 48 for 
coupling the links 45 with the lnks 47, respectively. Each piston rod 42 
is coupled with a coupling pin 49 for coupling each link 45 with each link 
48. Furthermore, a gear 50 is mounted on one end portion of the driving 
shaft 36 through a one-way clutch adapted to be turned on and off so as to 
transmit to the driving shaft 46 a rotational force oriented only in the 
direction indicated by the arrow a. Namely, when the gear 50 is driven so 
as to be rotated in the direction of the arrow a, the links 47 are rotated 
in the direction of the arrow a together with the driving shaft 46, so 
that the links 45 are also rotated in the direction of the arrow a in 
operative association with the links 48. Thus, since the piston rods 42 
are moved in the direction opposite to that of the arrow b, the chambers 
41 of the air cylinders 11 are set at a negative pressure and thus, the 
negative pressure prevails in the suction pads 12 communicating with the 
chambers 41, respectively. Meanwhile, when transmission of the rotational 
driving force from the gear 50 to the driving shaft 46 is stopped, the 
piston rods 42 are returned in the direction of the arrow b by an urging 
force of the return springs, thereby resulting in cancellation of the 
negative-pressure state of the chambers 41. 
Furthermore, four rollers 51 are rotatably mounted on one end portion of 
each holder plate 36. A pair of inner cams 52a and a pair of outer cams 
52b are secured to a driving shaft 53 so as to be, respectively, disposed 
above the rollers 51 such that the inner cams 52a are interposed between 
the outer cams 52b in the widthwise direction of the sheet transport path. 
A gear 54 is mounted on one end portion of the driving shaft 53 through a 
one-way clutch adapted to be turned on and off so as to transmit to the 
driving shaft 53 a rotational force oriented only in the direction 
indicated by the arrow a. Since a left portion of the suction mechanism is 
heavier than a right portion thereof with respect to the holder plates 36 
in FIG. 5, the holder plates 36 are so urged as to be pivoted about the 
shaft 13 in the counterclockwise direction in FIG. 5, so that the rollers 
51 are, respectively, brought into contact with outer peripheral faces of 
the inner cams 52a and the outer cams 52b and thus, the holder plates 36 
are prevented from being pivoted further at a certain pivotal angle. 
Accordingly, when the rotational driving force is transmitted from the 
gear 54 to the driving shaft 53 so as to rotate the inner cams 52a and the 
outer cams 52b in the direction of the arrow a together with the driving 
shaft 53, the holder plates 36 are pivoted about the shaft 13 in 
accordance with configurations of the outer peripheral faces of the inners 
cams 52a and the outer cams 52b, respectively. 
Referring to FIGS. 9a and 9b, there are shown the configurations of the 
inner cams 52a and the outer cams 52b, respectively. Each of the inner 
cams 52a and the outer cams 52b effects one complete rotation during each 
printing operation so as to pivot each suction pad 12 upwardly and 
downwardly upon one reciprocating pivotal movement of each holder plate 36 
such that the leading edge of the uppermost one of the photosensitive film 
sheets S stacked in the supply cassette 10 is lifted up through sucking 
thereof by the suction pads 12 as shown in FIG. 6, which operation will be 
described later. 
Next, the feed mechanism will be described, hereinbelow. The feed mechanism 
includes a pair of feed rollers 14. The feed rollers 14 are constituted by 
an elongated rollers 14a and a pair of plate-like rollers 14b held in 
contact with opposite end portions of the roller 14a, respectively. The 
rollers 14a and 14b are rotatably mounted on a pair of frames 61 
confronting each other. The frames 61 are rotatably supported, at lower 
ends thereof, by a shaft 62 and are urged at all times in the direction 
indicated by the arrow c in FIG. 4 by springs (not shown). A pair of 
rollers 63 are, respectively, mounted on central portions of opposite 
outer faces of the frames 61. It is so arranged that pivotal movements of 
the frames 61 are regulated at a certain pivotal angle through contact of 
the rollers 63 with a pair of cams 65 secured to a driving shaft 64. 
Furthermore, a gear 66 is mounted on one end portion of the driving shaft 
64 through a one-way clutch adapted to be turned on and off so as to 
transmit to the driving shaft 64 a rotational force oriented only in the 
direction indicated by the arrow d in FIG. 4. Moreover, since a pulley, a 
timing belt, etc. (not shown) for transmitting the rotational force of the 
driving shaft 64 are provided at one end of the shaft 62 and at one end of 
a rod portion 67 of the roller 14a, the roller 14a is driven for rotation 
thereof in the direction indicated by the arrow e in FIG. 4 and the 
rollers 14b in contact with the roller 14a are rotated by the roller 14a. 
Namely, each time the cam 65 is rotated, the frames 61 effect one 
reciprocating pivotal movement about the shaft 62, so that the feed 
rollers 14 are moved toward and away from the suction pads 12 at a height 
substantially equal to that of the leading edge of the film sheet S lifted 
up by the suction pads 12. When the feed rollers 14 are moved in the 
direction opposite to that of the arrow c in FIG. 4, the feed rollers 14 
grip therebetwen the leading edge of the film sheet S lifted up by the 
suction pads 12 so as to feed the film sheet S onto the support plate 15 
by the rotational force of the feed rollers 14. 
Hereinbelow, operations of the suction mechanism and the feed mechanism 
will be described with reference to FIGS. 9 to 11. Initially, at the time 
of the start of the sucking operation of the suction mechanism, points a1 
and b1 (FIGS. 9a and 9b) lying on the outer peripheral faces of the inner 
cams 52a and the outer cams 52b, respectively, are brought into contact 
with the rollers 51 and the holder plates 36 are pivoted about the shaft 
13 in the clockwise direction in FIG. 5, so that the suction pads 12 are 
positioned at an upper limit of their stroke as shown in FIG. 11a. In 
response to a supply start signal for starting supply of the film sheets 
S, the one-way clutch of the gear 54 is initially turned on so as to 
rotate the inner cams 52a and the outer cams 52b in the direction of the 
arrow a. When the inner cams 52a and the outer cams 52b are rotated 
through 90.degree. in the direction of the arrow a, points a2 and b2 lying 
on the outer peripheral faces of the inner cams 52a and the outer cams 
52b, respectively are brought into contact with the rollers 51 and the 
suction pads 12 are positioned at a lower limit of their stroke such that 
the suctions pads 12 are brought into contact with the upper face of the 
uppermost one of the film sheets S stacked in the supply cassette 10 as 
shown in FIG. 11b. At this time, the one-way clutch of the gear 50 is 
turned on to rotate the driving shaft so as to pivot the links 47 in the 
direction of the arrow a, so that the piston rods 42 are moved in the 
direction opposite to that of the arrow b and thus, the chambers 41 of the 
air cylinders 11 are set at a negative pressure, whereby the leading edge 
of the uppermost one of the film sheets S is sucked up by the suction pads 
12. 
Subsequently, when the inner cams 52a and the outer cams 52b are further 
rotated through 90.degree. in the direction of the arrow a, points a3 and 
b3 lying on the outer peripheral faces of the inner cams 52a and the outer 
cams 52b, respectively, are brought into contact with the rollers 51. 
Since a section of each of the outer cams 52b, which extends from the 
point b2 to the point b3, has a constant radius of curvature, the holder 
plates 36 corresponding to the outer cams 52b are not pivoted, so that the 
suction pads 12 corresponding to the outer cams 52b are held at the lower 
limit of their stroke. On the other hand, since a section of each of the 
inner cams 52a, which extends from the point a2 to the point a3, has radii 
of curvature increasing gradually in a path proceeding from the point a2 
to the point a3, the the holder plates 36 corresponding to the inner cams 
52a are pivoted about the shaft 13 in the clockwise direction in FIG. 5, 
so that the suction pads 12 corresponding to the inner cams 52a are raised 
to an intermediate point of their stroke as shown in FIG. 11c. Thus, since 
a central portion of the leading edge of the uppermost one of the film 
sheets S is lifted up by the suction pads 12 corresponding to the inner 
cams 52a and opposite side portions of the leading edge of the uppermost 
one of the film sheets S is depressed by the suction pads 12 corresponding 
to the outer cams 52b, only the uppermost one of the film sheets S can be 
positively sucked up by the suction mechanism. 
Thereafter, when the inner cams 52a and the outer cams 52b are further 
rotated through 90.degree. in the direction of the arrow a, points a4 and 
b4 lying on the outer peripheral faces of the inner cams 52a and the outer 
cams 52b, respectively, are brought into contact with the rollers 51. 
Since a section of each of the inner cams 52a, which extends from the 
point a3 to the point a4, has a constant radius of curvature, the holder 
plates 36 corresponding to the inner cams 52a are not pivoted, so that the 
suction pads 12 corresponding to the inner cams 52a are held at the 
intermediate point of their stroke. On the other hand, since a section of 
each of the outer cams 52b, which extends from the point b3 to the point 
b4, has radii of curvature increasing gradually in a path proceeding from 
the point b3 to the point b4, the holder plates 36 corresponding to the 
outer cams 52b are pivoted about the shaft 13 in the clockwise direction 
in FIG. 5, so that the suction pads 12 corresponding to the outer cams 52b 
are raised to the intermediate point of their stroke as shown in FIG. 11d 
and thus, the leading edge of the lifted film sheet S is set horizontally. 
Then, when the inner cams 52a and the outer cams 52b are further rotated 
through 90.degree. in the direction of the arrow a so as to effect one 
complete rotation, the points a1 and b1 are brought into contact with the 
rollers 51, so that all the suction pads 12 are positioned at the upper 
limit of their stroke as shown in FIGS. 11e and 6. Namely, upon one 
complete rotation of the inner cams 52a and the outer cams 52b and through 
the sucking operation of the air cylinder 11, the leading edge of the 
uppermost one of the film sheets S is horizontally raised up to the upper 
limit of the stroke of the suction pads 12. 
When this state where the leading edge of the uppermost one of the film 
sheets S is raised up to the upper limit of the stroke of the suction pads 
12 is detected by a proper sensor means, the one-way clutch of the gear 66 
is turned on so as to rotate the cams 65 in the direction of the arrow d. 
Thus, since contact points of each of the rollers 63 with respect to each 
of the cams 65 are displaced from a point c1 to a point c2 (FIG. 10), the 
frames 61 are pivoted about the shaft 62 in the direction opposite to that 
of the arrow c such that the feed rollers 14 grip therebetween the leading 
edge of the lifted film sheet S. At the same time, the one-way clutch of 
the gear 50 is turned off, so that the piston rods 42 are returned in the 
direction of the arrow b and thus, the negative-pressure state in the 
suction pads 12 is cancelled. 
The feed rollers 14 are rotated simultaneously with the start of the above 
described displacement of the contact points of each of the rollers 63 
with respect to each of the cams 65 from the point c1 to the point c2. As 
soon as the feed rollers 14 grip therebetween the leading edge of the film 
sheet S, the feed rollers 14 carry onto the support plate 15 the film 
sheet S which is not subjected to suction of the suction pads 12 any more. 
The cams 35 effect one complete rotation during each feeding operation of 
the film sheet S. As the contact points of each of the rollers 63 with 
respect to each of the cams 65 are displaced from the point c2 to the 
point c1, the feed rollers 14 feed the film sheet S forwardly while being 
moved forwardly, i.e., in the direction of the arrow c. Meanwhile, 
rotation of the feed rollers 14 is stopped at the time when the film sheet 
S has been fed onto the support plate 15. The above described stopping of 
rotation of the feed rollers 14 is performed so as to prevent, as much as 
possible, unstable transport of the film sheet S due to its vibration 
resulting from drive of the feed rollers 14. 
In the above described operations of the suction mechanism and the feed 
mechanism, the uppermost film sheet S is positively lifted up one sheet at 
a time from the film sheets S stacked in the supply cassette 10 by the 
suction mechanism through time lag in upward movements of the suction pads 
12 so as to be fed onto the support plate 15 by the feed mechanism. In 
this embodiment, the upward and downward movements of the suction pads 12 
are controlled in accordance with the configurations of the inner cams 52a 
and the outer cams 52b. However, if the feed rollers 14 are capable of 
gripping therebetween the leading edge of the film sheet S disposed at the 
intermediate point (FIG. 11d) of the stroke of the suction pads 12, the 
operation of FIG. 11e can be deleted. In this case, each of the inner cams 
52a and the outer cams 52b is so formed as to have three outer peripheral 
sections extending at intervals of 120.degree., repectively. In the case 
where the intermediate point of the stroke of the suction pads 12, to 
which the leading edge of the film sheet S is lifted by the suction pads 
12, is quite different from a height of the sheet transport path defined 
by the feed rollers 14, the operation of FIG. 11e is effectively performed 
as in this embodiment. Namely, when the intermediate point of the stroke 
of the suction pads 12 is set at as high a position as possible in FIG. 
11c, the uppermost film sheet S is effectively sucked up from the stack of 
the film sheets S. However, at this time, since the central portion of the 
film sheet S is raised high to a large extent, the opposite side portions 
of the film sheet S are shifted towards the suction pads 12 corresponding 
to the inner cams 52a, so that the leading edge of the film sheet S is in 
a wavy state when the suction pads 12 corresponding to the outer cams 52b 
lift up the film sheet S through suction thereof, whereby such an 
undesirable phenomenon may take place that the feed rollers 14 are not 
capable of gripping therebetween the film sheet S properly. In this 
embodiment, in order to eliminate such waviness of the film sheet S, the 
suction pads 12 are once stopped at the intermediate point between the 
lower limit and the upper limit of the stroke of the suction pads 12. 
It should be noted that the sucking operations of the suction mechanism and 
the feed operations of the feed mechanism are controlled by a sequence 
circuit or a microcomputer through a combination of signals of a print 
switch, timers, etc. and these control devices are provided in the control 
cabinet 26 together with other control components for the push lever 16, 
the stopper 18, etc. 
The suction mechanism of the image recording apparatus P can be modified in 
various ways. For example, it can be so modified that the suction pads 12 
are moved upwardly and downwardly by another drive means in place of the 
inner cams 52a and the outer cams 52b. It an be also be modified such that 
the suction pads 12 corresponding to the outer cams 52b are initially 
lifted and then, the suction pads 12 corresponding to the inner cams 52a 
are lifted. It is needless to say that the number of the suction pads 12 
is not restricted to four. Furthermore, it can also be arranged such that 
the feed rollers 14 of the feed mechanism are moved horizontally without 
being moved in the arcuate path so as to grip therebetween the leading 
edge of the film sheet S. The suction mechanism and the feed mechanism of 
the image recording apparatus P can be applied to a laser beam printer, an 
X-ray camera for medical use, etc. 
Consequently, in the suction mechanism of the image recording apparatus P, 
since the suction pads sucking the leading edge of the film sheet are 
upwardly moved through a time lag between the opposite outer suction pads 
and the inner suction pads, the uppermost film sheet can be positively 
sucked up one sheet at a time from even a stack of the film sheets held in 
close contact with one another. 
Furthermore, in the feed mechanism of the image recording apparatus P, 
since the suction mechanism is not required to be moved but the feed 
rollers are moved so as to grip therebetween the leading edge of the film 
sheet, the arrangement for moving the feed rollers can be made compact in 
size and simple in structure as compared with conventional arrangements 
for moving the suction mechanism. In addition, since the feed rollers are 
moved in the feed direction of the film sheets while being rotated so as 
to feed the film sheet onto the support plate, the film sheet can be fed 
more rapidly than in the case where the feed rollers are fixedly provided, 
whereby the printing speed of the image recording apparatus can be 
increased. 
Although the present invention has been fully described by way of example 
with reference to the accompanying drawings, it is to be noted here that 
various changes and modifications will be apparent to those skilled in the 
art. Therefore, unless otherwise such changes and modifications depart 
from the scope of the present invention, they should be construed as being 
included therein.