Description of the Related Art According to a conventional method for printing captions on films for motion pictures, movies, etc., a flexible film is pressed on a copperplate on which a desired caption is embossed, so that the caption is imprinted on the film.

In a conventional film pressing system of a caption printer using the conventional method, the copperplate is placed on a stand, and a film drawn out from a winding roll on which the film is wound is positioned above the copperplate. Also, a pressing plate of an actuator moving down from above presses the film onto the copperplate, so that the caption is imprinted on the lower surface of the film.

In order to press the film by the conventional film pressing system, the pressing plate of the actuator is lowered down by stepping on a lever, or a hingedly assembled pressing plate is pivoted by operating a handle.

Therefore, since the pressing plate is not automatically, but manually operated, the automation is not achieved in printing captions on films by the conventional

film pressing system. For this reason, the conventional film pressing system requires considerable time and labor in imprinting captions on films by a plurality of copperplates, and this problem becomes more severe especially when hundreds of copperplates are used. Thus, the conventional film pressing system is relatively inferior in a viewpoint of competence in the market.

Moreover, since the pressing plate is operated only by an operator's manual labor, the pressing force by the pressing plate is not uniform during the entire caption imprinting process, and thereby the imprinted states of the captions are not uniform and sometimes unclear.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and it is an object of the present invention to provide a film pressing system of a caption printer, in which a pressing plate is actuated by a driving force of a motor and a film is pressed with a uniform force by the pressing plate, so that not only a complete automation is achieved in printing captions on films, but also uniformly clear captions are imprinted on the films.

In accordance with one aspect, the present invention provides a film pressing system of a caption printer, the film pressing system comprising: an actuator vertically disposed in a casing; a motor for automatically ascending and descending the actuator in the casing ; a pressing plate fixed to a lower end of the actuator; and a stand disposed directly under-the pressing plate, the stand clamping a copperplate on which a desired caption is embossed,

wherein the pressing plate presses desired cuts of a film on the copper plate so as to imprint the desired caption on the film when the actuator is descended, while the actuator is automatically ascended when it is not necessary to imprint a caption on the film.

Preferably, the actuator has a guiding pole integrated with a top of the actuator, the guiding pole extending upward through a top of the casing, the guiding pole having an actuator spring for exerting an upward biasing force on the actuator.

In the film pressing system, a roll ring and an eccentric cam are mounted on a side of the actuator, and a rotation shaft is integrated with the eccentric cam. The roll ring and the eccentric cam are in rolling contact with each other at their circumferences, and the rotation shaft is rotated by the motor so that the eccentric cam is rotated about the rotation shaft. The actuator is descended when a peripheral portion of the eccentric cam more distanced from a center of the eccentric cam is in contact with the roll ring to push the roll ring.

In accordance with another aspect, a film pressing system of the present invention further comprises a clutching section for switching an operation of the pressing plate between being prevented from imprinting and being capable of imprinting a caption on the film by moving up and down the rotation shaft together with the eccentric cam integrated with the eccentric cam. The clutching section comprises a pivoting cam, a cam ring, and a piston rod. The rotation shaft is fixedly inserted through an eccentric hole formed at an eccentric position of the pivoting cam, and the cam ring is fixed around the pivoting cam and is jointed to the piston rod. The alternating movements of the piston rod in the cylinder rotate the pivoting cam to move up and down the eccentric cam.

BRIEF DESCRIPTION OF THE DRAWINGS The above objects, and other features and advantages of the present invention will become more apparent after a reading of the following detailed description when taken in conjunction with the drawings, in which: Fig. la is an exploded perspective view of a film pressing system of a caption printer according to an embodiment of the present invention; Fig. 2 is a sectional view of the film pressing system of a caption printer shown in Fig. la ; and Fig. 3 is a perspective view of the caption printer shown in Fig. la.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS A film pressing system of a caption printer according to a preferred embodiment of the present invention will be described in detail hereinafter with reference to the accompanying drawings.

As shown in Figs. 1 to 3, a film pressing system according to a preferred embodiment of the present invention includes a casing 10 having a rectangular box shape installed on the front surface of a caption printer 1 for printing captions on films of movies, photographs, etc. The casing 10 contains lubrication oil 11 for ensuring a smooth operation of parts.

In the casing 10, disposed is an actuator 20 vertically extending and movably supported by bearings 21 and 21a respectively surrounding upper and lower portions of its cylindrical periphery. The bearings 21 and 21a maintain the vertical movement of the actuator 20 stable and linear without yawing.

With the top of the actuator-20 is integrated a guiding pole 25 extending upward through the top of the casing 10. The guiding pole 25 is provided with an actuator

spring 22 for exerting an upward biasing force on the actuator 20. The actuator 20 has a pressing plate 23 integrated with the bottom of the actuator 20.

The back of the actuator 20 is cut out to form a flat guiding surface 20a on which a roll ring 24 and an eccentric cam 31 are mounted. The roll ring 24 and the eccentric cam 31 are in rolling contact with each other at their circumferences, and the eccentric cam 31 is driven by a motor 50 to ascend or descend the actuator 20.

That is, the actuator 20 is lowered down when the peripheral portion of the eccentric cam 31 more distanced from the center thereof is in contact with the roll ring 24 to push the roll ring 24, while the actuator 20 is elevated by the attracting force of the actuator spring 22 when the peripheral portion of the eccentric cam 31 nearer to the center thereof is in contact with the roll ring 24, during the rotation of the eccentric cam 31 around its rotation shaft 32. This construction including all the parts for ascending and descending the actuator 20 as above constitutes a driving section 30.

The rotation shaft 32 of the eccentric cam 31 is assembled with a pivoting cam 41 in such a manner that the rotation shaft 32 is fixedly inserted through an eccentric hole 41a formed at an eccentric position of the pivoting cam 41. A cam ring 42 is fixed around the pivoting cam 41 and has a connecting arm 42a jointed by a pin to a piston rod 43a of a cylinder 43, so that the alternating movement of the piston rod 43a rotates the pivoting cam 41 to ascend or descend the eccentric cam 31 on the flat guiding surface 20a.

That is, when the piston rod 43a alternates through the cylinder 43, the pivoting cam 41 together with the cam ring 42 connected to the piston rod 43a-rotates to ascend or descend the rotation shaft 32 inserted through the eccentric hole 41a of the pivoting cam 41. Accordingly, the actuator

20 integrated with the rotation shaft 32 ascends or descends on the flat guiding surface 20a, correspondingly to the rotation shaft 32.

Therefore, in the state that the eccentric cam 31 is ascended by the operation of the piston rod 43a, the eccentric cam 31 is not in contact with the roll ring 24 on the flat guiding surface 20a, so that the rotation of the eccentric cam 31 can not ascend and descend the actuator 20.

On the other hand, in the state that the eccentric cam 31 is lowered, the eccentric cam 31 is in contact with the roll ring 24 on the flat guiding surface 20a, so that the rotation of the eccentric cam 31 can ascend and descend the actuator 20. The parts in relation to the ascending and the descending of the eccentric cam 31 as above perform as a clutching section 40 for connecting and cutting off the driving force.

Under the pressing plate 23 is located a film 70 drawn out from a film-winding roll, and under the film 70 is located a copperplate 80 clamped on a stand 81. A caption or desired letters are embossed on the copperplate 80.

At the rear end of the rotation shaft 32 of the eccentric cam 31 is formed a gear 32a engaged with a timing belt 51. The timing belt 51 is also engaged with a pulley of the motor 50, so that the driving force is transferred from the motor 50 through the timing belt 51 to the gear 32a of the rotation shaft 32.

In the meantime, a tightening lever 60 is pivotally -assembled with the pivoting cam 41 and is supported by a lever spring 60a exerting a biasing force to the tightening lever 60. The tightening lever 60 is provided with a roller 61 assembled with the distal end thereof. The tightening lever 60 stands on the timing belt 51 in such a manner that the roller 61 of the tightening lever-60 can roll on the timing belt 51. Therefore, when the timing belt 51 is loosened to lose its tension according to the ascending or

the descending of the rotation shaft 32 of the eccentric cam 31, the tightening lever 60 elastically presses the timing belt 51 to make it recover its tension necessary for transferring the driving force from the motor 50 to the gear 32a.

In the film pressing system of the present invention having the construction as described above, the actuator 20 encased in the casing 10 is supported by the bearings 21 and 21a in a stable manner. In this state, the actuator 20 is lowered down through the operation of the eccentric cam 31 driven by the motor 50. Then, the pressing plate 23 provided at the actuator 20 presses the film 70 on the copperplate 80, so that the letters or the caption embossed on the copperplate 80 is impressed on the film. In result, a clear caption 70a is printed on the film 70.

Further, the eccentric cam 31 can selectively come into contact with the roll ring 24 of the actuator 20 by moving the eccentric cam 31 up and down through the operation of the pivoting cam 41. This means that the caption 70a may be formed on only the required cuts of the film 70 by selectively lowering the actuator 20 on the required cuts, that is, by the operation of the clutching section 40.

In the film pressing system of the present invention as described above, the actuator 20 encased in the casing 10 is elevated or lowered by a constant driving force of eccentric cam 31 driven by the motor 50. Therefore, the pressing force applied to the film 70 by the actuator 20 is maintained always constant while the caption 70a is formed on the film 70, so that uniformly clear captions can be formed on all desired cuts of the film.

Further, the motor 50 for operating the actuator 20 and the cylinder 43 for operating the-pivoting cam 41 are operated by an electric signal from a control section (not shown) installed in the caption printer 1. Accordingly, the

present invention provides an advantage in that the captions 70a can be automatically formed on the film 70. This automation reduces manufacturing cost and increases the productivity in printing captions on film. Therefore, the present invention provides a competitive film pressing system of a caption printer, which has overcome the problems of the prior art.

While there has been illustrated and described what is considered to be a preferred specific embodiment of the present invention, it will be understood by those skilled in the art that the present invention is not limited to the specific embodiment thereof, and various changes and modifications and equivalents may be substituted for elements thereof without departing from the true scope of the present invention.