Abstract:
A camera employing a film provided with a magnetic memory portion includes a magnetic head for writing data in and/or reading out data from the magnetic memory portion of the film, and a retaining device for retaining the magnetic head having an axis of rotation about which said magnetic head is freely rotatable during a read and/or write operation in such a manner as to follow a film deviation, rotatable about an axis being parallel to a direction in which the film is transported.

Description:
This application is a continuation of application Ser. No. 07/975,001, filed Nov. 12, 1992, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an improvement in a camera employing a film provided with a magnetic memory portion and having a magnetic head which comes into contact with the magnetic memory portion of the film to write data to and read out data from the magnetic memory portion. 
     2. Description of the Related Art 
     A camera having a retaining mechanism for retaining a magnetic head have been proposed in, for example, Japanese Patent Laid-Open No. Hei 3-168624. Such a camera will be described below with reference to FIGS.  5 ( a ),  5 ( b ) and  5 ( c ). 
     A magnetic head  101  is fixed to the distal end portion of a retaining member  103 . The retaining member  103  is rotates about a support shaft  102  which extends perpendicularly to the direction indicated by a bidirectional arrow A, shown in FIG.  5 ( a ), in which a film is transported. 
     The magnetic head  101  has a core  101   a  having a gap portion  101   b.  Core  101   a  and gap portion  101   b  are disposed within magnetic head  101 . The gap portion  101   b  is pressed against the magnetic memory portion of the film  105  by means of the elastic force of a pressing spring  104  during transporting of the film, whereby writing of data in and/or reading of data from the magnetic memory portion can be made possible. 
     U.S. Pat. No. 4,947,196 discloses a structure which movably retains the magnetic head by a flexible member and which restricts the movement of the magnetic head in directions other than a predetermined direction. 
     However, the aforementioned conventional techniques have the following problems. 
     That is, in the former technique, the film  105  is retained in a stepped portion (a tunnel portion) established by an inner rail and an outer rail of the camera. Since the step difference of the stepped portion is larger than that of the film  105 , the film  105  is allowed to move freely in the stepped portion in the direction of the thickness of the film (which is indicated by a bidirectional arrow B in FIG.  5 ( b )) during the transporting of the film. On the other hand, when data is written to or read out from the magnetic memory portion of the film  105  by the magnetic head  101 , the gap portion  101   b  of the magnetic head  101  must be brought into close contact with the magnetic memory portion. Since the film  105  fluctuates in the direction indicated by the bidirectional arrow B during the transporting of the film, the magnetic head  101  must follow this fluctuation of the film  105 . 
     However, the gap portion  101   b  of the magnetic head  101  is perpendicular to the direction in which the film is transported and has a width of several microns. If the support shaft  102  which allows rocking of the magnetic head  101  through the retaining member  103  is perpendicular to the direction in which the film is transported, as in the case of the aforementioned conventional technique, a gap C, shown in FIG.  5 ( c ), is formed between the gap portion  101   b  of the magnetic head  101  and the magnetic memory portion of the film  105  by the fluctuation of the film  105 . In that case, the gap portion  101   b  may be prevented from being kept in close contact with the magnetic memory portion, thus preventing writing of data to and/or reading out of data from the magnetic memory portion of the film. 
     Furthermore, during the assembly, fine adjustment of, for example, the support shaft  102  and the pressing spring  104  is required, thus increasing manufacturing costs. 
     However, as a practical matter it is difficult for the flexible member to allow the movement of the magnetic head in a particular direction and to restrict the movement thereof in the other directions because deformation of the flexible member is caused by complex composition of flexures in a plurality of directions. Thus, the gap portion  101   b  of the magnetic head may not be maintained in close contact with the magnetic memory portion of the film due to the fluctuation of the film, as in the case of the former technique. Accordingly, writing of data to and/or reading of data from the magnetic memory portion of the film by the magnetic head may be made impossible. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a camera employing a film with a magnetic memory portion or a device for such a camera, which enables a close contact between a gap portion of a magnetic head and the magnetic memory portion of the film to be maintained so as to reliably write data to and/or read out of data from the magnetic memory portion, even if the film fluctuates. 
     In one aspect of the present invention, there is provided a camera, or a device for a camera, employing a film provided with a magnetic memory portion, which comprises a magnetic head for writing data to and/or reading out data from the magnetic memory portion of the film, and retaining means for retaining the magnetic head in such a manner as to be rotatable about a shaft which extends in parallel with a direction in which the film is transported. 
     Other aspects of the present invention will become apparent from the following description of the preferred embodiments of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the essential parts of a camera in accordance with a preferred embodiment of the present invention; 
     FIG. 2 is an exploded perspective view of a film pressure plate unit in the camera of FIG. 1; 
     FIG. 3 is a perspective view of the film pressure plate unit of FIG. 2 as viewed from the film side; 
     FIGS.  4 ( a ) and  4 ( b ) are perspective views illustrating the state of individual components of the film pressure plate unit of FIG. 2 at the time of the writing data to and/or reading out data and during the exposure operation, respectively; and 
     FIGS.  5 ( a ),  5 ( b ), and  5 ( c ) are plan views illustrating a conventional magnetic head and a support shaft for rotatably supporting the magnetic head. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment of the present invention will be described below with reference to FIGS. 1 through 4. 
     Referring first to FIG. 1, a camera body  1  has a cartridge chamber la and a spool chamber  1   b.  A film  3  having a magnetic memory portion is accommodated in a film cartridge  2 . A spool  4  is rotated by a motor and a transmission gear train, which are not shown, to wind the film  3 . A film pressure plate  5  is fixed to the camera body  1 . 
     FIG. 2 is an exploded perspective view of the film pressure plate unit of the camera. 
     A slider holder  6  has bearing portions  6   a  and  6   b  and spring holding portions  6   c  and  6   d.  The film pressure plate  5  has spring holding anchors  7  and  8  formed therein. Slide springs  9  and  10 , respectively, are held by the spring holding portion  6   c  and the spring holding anchor  7  and by the spring holding portion  6   d  and the spring holding anchor  8  to urge the slide holder  6  upward. A head holder  11  has a rotary shaft  11   a,  an arm  11   b  and spring-receiving portions  11   c  and  11   d.  The rotary shaft  11   a  is parallel to the direction in which the film is transported and is rotatably retained by the bearing portions  6   a  and  6   b  of the slide holder  6 . A magnetic head  12  for writing data to and/or reading data from the magnetic memory portion of the film  3  integrally includes a mounting baseboard  12   a  and guide shafts  12   b  and  12   c.  The magnetic head  12  is fixed to the head holder  11  by means of screws  13  and  14 . 
     One end of each of pressing spring  15  and pressing spring  16  is in abutment with their corresponding spring-receiving portion  11   c  and spring-receiving portion  11   d  of the head holder  11  so as to cause the head holder  11  to rotate about the rotary shaft  11   a  and thereby cause the magnetic head  12  to press against a surface of the film  3 . A spring press  17  is fixed to the slide holder  6  by means of screws  18 ,  19 ,  20  and so on. The spring press  17  receives the other ends of the pressing springs  15  and  16 . Also, the spring press  17  has a slide guide shaft  21 . A slide guide  22  is fixed to the film pressure plate  5  by means of screws  23  through  26 . The slide guide  22  has an elongated hole  22   a  which guides the slide guide shaft  21  in such a manner as to be slidable in the vertical direction and also rotatable. 
     A motor mounting baseboard  27  is fixed to the camera body  1 . A motor  28  is fixed to the motor mounting baseboard  27 . A pinion gear  29  fixed to the output shaft of the motor  28  meshes with a two-speed gear  30 , which is in turn meshes with a two-speed gear  31 . A smaller gear (not shown) of the two-speed gear  31  meshes with an idle gear  32 , which in turn meshes with a rack portion  33   d  of a slide lever  33 . The slide lever  33  also has elongated holes  33   a  and  33   b,  a tapered portion  33   c  and an arm  33   d.  Guide shafts  34  and  35  fixed to the film pressure plate  5  are fitted in the elongated holes  33  and  33   b  to retain the slide lever  33  in such a manner as to be slidable to the right and left, as viewed in FIG. 2. A phase contact piece  36  is fixed to the arm  33   d  of the slide lever  33 . A phase baseboard  37  is fixed to the film pressure plate  5  to detect in cooperation with the phase contact piece  36  that the slide lever  33  has reached the left and right ends of travel. 
     In FIG. 3, the magnetic head  12  has a first track forming portion  12   d,  a second track forming portion  12   e  and a third track forming portion  12   f.  Each of the tracks  12   d  through  12   f  has a gap portion  12   g  which is perpendicular to the direction in which the film is transported. Each of the track forming portions  12   d  through  12   f  has a width ranging from 0.5 mm to 1 mm. The width of the gap portion  12   g  is several microns. The guide shafts  12   b  and  12   c  are always in contact with the lower end portion of the film  3  by the slide springs  9  and  10  (see FIG.  2 ). 
     In the structure arranged in the manner described above, the gap portion  12   g  of the magnetic head  12  is rotated about the rotary shaft  11   a  by the pressing springs  15  and  16 , so that the gap portion  12   g  can be always elastically pressed against the surface of the film. 
     Thus, even if the film  3  fluctuates in the direction of the thickness of the film  3  in the stepped portion (the tunnel portion ) between the inner and outer rails of the camera body  1  during a film transporting operation, the gap portion  12   g  of the magnetic head  12  can be maintained in contact with the magnetic memory portion. 
     FIG.  4 ( a ) is a perspective view illustrating the state of the components during the film transporting operation, i.e., at the time the magnetic head  12  writes data in and/or reads out data from the magnetic memory portion of the film  3 . 
     When data is written to and/or read out from the magnetic memory portion of the film  3 , the motor  28  is driven clockwise to slide the slide lever  33  to the left through the transmission gears  30  through  32 . After it is detected by the phase contact piece  36  and the phase base board plate  37  that the slide lever  33  has reached the left end, the drive of the motor  28  is stopped, whereby the gap portion  12   g  of the magnetic head  12  is pressed against the magnetic memory portion of the film  3  by the elastic force of the pressing springs  15  and  16 , as stated above, because the slide lever  33  does not operate on the head holder  11  at all. 
     FIG.  4 ( b ) is a perspective view illustrating the state during exposure of the film  3 . 
     When the film  3  is exposed, the motor  28  is driven counterclockwise to slide the slide lever  33  to the right through the transmission gears  30  through  32 . At that time, the tapered portion  33   c  of the slide lever  33  is moved below the arm  11   b  of the head holder  11 , pushing the arm  11   b  up, thereby rotating the head holder  11  about the rotary shaft  11   a  against the pressing springs  15  and  16 , whereby the close contact between the magnetic head  12  and the film  3  is released. In this way, an adverse influence to the flatness of the film  3  during the exposure, caused by the pressing of the magnetic head  12  against the film, can be eliminated. 
     In order that the rotary shaft  11   a  of the head holder  11  maintains close contact between the magnetic head  12  and the surface of the film  3  in a constant state as much as possible even when the film  3  fluctuates in the direction of the thickness thereof, it is desirable that the rotary shaft  11   a  be separated from the magnetic head  12  by the longest possible distance. 
     Since the member  11  for retaining the magnetic head  12  is arranged to be rotatable about the rotary shaft  11   a  and the rotary shaft  11   a  is parallel with the direction in which the film is transported, even if the film  3  fluctuates in the direction of the thickness of the film during film transporting operation, the close contact between the gap portion  12   g  of the magnetic head  12  and the magnetic memory portion of the film  3  can be reliably maintained. Thus, reliable writing of data to and/or reading out data from the memory portion of the film  3  is possible. 
     While the present invention has been described with respect to what is presently considered to be the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment. To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.