Abstract:
An information recording-reproducing apparatus is provided which effects any one of recording of information on an information recording medium and reproduction of the information from the information recording medium by a head while relatively moving a carriage, on which the information recording medium has been mounted, and the head, wherein the apparatus satisfies the following relationship 
     
       
           Y &lt;{(0.8−3.0)/(800−150)} X +3.5 
       
     
     wherein X is a velocity (mm/sec) of continuous movement of a moving member of the carriage or head, and Y is a movement distance (mm) of the center of gravity in the whole apparatus.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an information recording-reproducing apparatus which effects any one of recording of information on an information recording medium and reproduction of the information from the information recording medium by a head while relatively moving a carriage, on which the information recording medium has been mounted and the head. 
     2. Related Background Art 
     There have heretofore been a magnetic system and an optical system as conventional recording systems for information recording mediums. The information recording mediums are in the form of a tape, disk, card or the like. These recording systems and medium forms are properly used according to purpose. Magnetic cards of the magnetic system, which are information recording mediums in the form of a card, are excellent in ease of putting away and portability and are hence widely used in card systems such as cash dispensers. 
     In recent years, the quantity of information operated by the card systems has increased by the influence of an information-oriented age, and so it has been difficult to cope with such increase in quantity of information by magnetic cards. In addition, the magnetic cards are often forged and hence offer a great social problem. There is thus a demand for development of an information recording medium high in safety. 
     In view of the foregoing circumstances, attention is paid to an optical card which is an information recording medium of the optical system in the form of a card. The optical card has such merits as it has a capacity as large as several M bits, and is easy to mass produce and cheap. In addition, the optical card is of an additionally writing type and is hence incapable of rewriting information, thereby making forgery difficult and leaving histories. The optical card is an information recording medium high in safety even from these points of view. 
     An example of such a conventional optical card is illustrated in FIG.  1 . FIG. 1 is a plan view of optical card C. The external shape of optical card C is rectangular. n (n being an integer of 2 or greater) information tracks  10   1 ,  10   2 ,  10   3 , . . . ,  10   n−1 ,  10   n  are arranged at intervals of several microns in parallel with one another in a direction parallel to the longer sides of optical card C. 
     An information recording-reproducing apparatus used for such an optical card is so designed that a light spot several μm in diameter is formed by a light beam between the information tracks of the optical card to record or reproduce information. The information recording-reproducing apparatus is also so designed that the optical card and an optical head are driven in directions perpendicular to each other to scan the optical card while causing the light beam to follow the information track in parallel. 
     As illustrated in, for example, FIG. 2, an opening  2  for taking an optical card C in and out is provided in a casing  1  of the conventional information recording-reproducing apparatus, and a carriage  3  mounting optical card C thereon is movably installed in the interior of casing  1 . A pair of rollers  4  for taking optical card C on and out of carriage  3  is provided between opening  2  and carriage  3 . The pair of rollers  4  is driven by a driving motor (not illustrated) and feeds optical card C, being held therebetween. An optical head  5 , in which an optical pickup (not illustrated) has been installed, is provided above carriage  3 . Optical head  5  serves to focus a laser beam on optical card C to record or reproduce information. 
     Optical card C is flatly held on carriage  3  to position and align it on carriage  3  in such a manner that the direction of the information tracks of optical card C accurately coincides with the moving direction of carriage  3 . Carriage  3  is provided so as to permit its reciprocative rectilinear movement in the direction of the information tracks of optical card C, and optical head  5  is provided so as to permit its reciprocative rectilinear movement in a direction perpendicular to the direction of the information tracks of optical card C. Carriage  3  is driven by a driving mechanism comprised of a belt  6 , pulleys  7   a  and  7   b , a driving motor (not illustrated), etc., and optical head  5  is also driven by a driving mechanism (not illustrated). The moving range of carriage  3  is determined by a light-screening plate  8  provided on the lower surface of carriage  3  and optical sensors  9   a  and  9   b  provided on the base of casing  1 . 
     Incidentally, in the above-described information recording-reproducing apparatus, carriage  3  is moved in the direction of the information tracks of optical card C, and optical head  5  is moved in the direction perpendicular to the information tracks of optical card C. However, there is also known an information recording-reproducing apparatus in which carriage  3  is moved in a direction perpendicular to the information tracks of optical card C, and optical head  5  is moved in the direction of the information tracks of optical card C. 
     On the other hand, with the development of digital communication techniques and the servicing of communication networks in recent years, information apparatus called mobile equipment are positively used not only indoors but also outdoors. From such a point of view, the above-described information recording-reproducing apparatus is also required to make it possible to be positively used outdoors for making the best use of the excellent portability of optical card C. Therefore, it is desirable that the information recording-reproducing apparatus be made small in size and light in weight to improve its portability and can be held in one hand so as to be easily operated. 
     In the conventional information recording-reproducing apparatus, however, carriage  3  and optical head  5  are relatively moved, and so the center of gravity of the apparatus comes to move repeatedly. Therefore, when an operator holds the apparatus in his hand to operate it, the operability and stability thereof become poor, and the apparatus may fall from the hand to break down in the worst case. In this case, if the mass of the apparatus may be reduced to, for example, about 100 g, the influence by the movement of the center of gravity is lightened to prevent the operability and stability from being deteriorated. It is however difficult under circumstances to actually reduce the mass of the apparatus to lighter than 300 g. 
     In order to improve such a problem, it is considered to join a balance weight, which has the same mass as carriage  3  or optical head  5  and interlocks in an opposite direction, to carriage  3  or optical head  5 . However, in this case, the driving motor for driving carriage  3  or optical head  5  comes to drive the balance weight as well, and so it is necessary to make the driving motor larger. Accordingly, a new mass of the balance weight and moreover an increased mass by the enlargement in size of the driving motor are added to the mass of the apparatus. It is hence expected that the mass and size of the apparatus are increased to impair the portability thereof. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an information recording-reproducing apparatus which can solve the above-described problems involved in the prior art and has high operability and stability upon operation with the apparatus held in an operator&#39;s hand. 
     The above object can be achieved by the present invention described below. 
     According to a first embodiment of the present invention, there is provided an information recording-reproducing apparatus which effects at least any one of recording of information on an information recording medium and reproduction of the information from the information recording medium by a head while relatively moving a carriage, on which the information recording medium has been mounted, and the head, wherein the apparatus satisfies the following relationship 
       Y&lt;{( 0.8−3.0)/(800−150)} X +3.5 
     wherein X is a velocity (mm/sec) of continuous movement of a moving member comprised of the carriage or head, and Y is a movement distance (mm) of the center of gravity in the whole apparatus. 
     According to a second embodiment of the present invention, there is provided an information recording-reproducing apparatus which effects at least any one of recording of information on an information recording medium and reproduction of the information from the information recording medium by a head while relatively moving a carriage, on which the information recording medium has been mounted, and the head, wherein the apparatus satisfies the following relationship 
     
       
           Z&lt;{( 0.014−0.045)/(800−150)} X +0.052 
       
     
     wherein X is a velocity (mm/sec) of continuous movement of a moving member comprised of the carriage or the head, and Z is a mass ratio of the moving member to the whole apparatus. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view illustrating an example of the conventional optical cards. 
     FIG. 2 is a schematic view illustrating an example of the conventional information recording-reproducing apparatus making use of the optical card shown in FIG.  1 . 
     FIG. 3 is a schematic view illustrating an information recording-reproducing apparatus according to the first embodiment of the present invention. 
     FIG. 4 diagrammatically illustrates the relationship between the velocity of a moving member and the movement distance of the center of gravity in the apparatus in the first embodiment. 
     FIG. 5 diagrammatically illustrates the relationship between the velocity of a moving member and the mass ratio of the moving member to the apparatus in the second embodiment of the present invention. 
     FIG. 6 is a schematic view illustrating an information recording-reproducing apparatus according to a third embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will hereinafter be described in detail on the basis of the embodiments. In the following embodiments, the conventional optical card illustrated in FIG. 1 is used as an information recording medium. 
     FIG. 3 is a fragmentary sectional view of an information recording-reproducing apparatus according to the first embodiment of the present invention. As an information recording medium, there is used such an optical card C of a credit card size as illustrated in FIG. 1, which optically records and/or reproduces information. An opening  12  for causing optical card C to go through a casing  11  of the information recording-reproducing apparatus is provided in a side of casing  11 , and a carriage  13  mounting optical card C thereon is movably installed in the interior of casing  11 . A pair of rollers  14  as a feeding means for taking optical card C on and out of carriage  13  is provided in the vicinity of opening  12  in the interior of casing  11 . The pair of rollers  14  is driven by a driving motor (not illustrated) and feeds optical card C with it held therebetween. An optical head  15 , in which an optical pickup (not illustrated) has been installed, is movably provided above carriage  13 . 
     Carriage  13  is provided so as to permit its reciprocative rectilinear movement in the direction of the information tracks of optical card C, and optical head  15  is provided so as to permit its reciprocative rectilinear movement in a direction perpendicular to the moving direction of carriage  13 . A belt  18  supported by a pair of pulleys  16  and  17  is joined to carriage  13 , and any one of pulleys  16  and  17  is connected to a driving motor (not illustrated). Optical head  15  is also driven by a driving mechanism similar to that used in carriage  13 . 
     A light-screening plate  19  is provided so as to project from the lower surface of carriage  13 , and optical sensors  20  and  21  for detecting the position of light-screening plate  19  are installed with an interval on casing  11 . A distance L between optical sensors  20  and  21  is equal to or somewhat shorter than the length of each information track of optical card C extending longitudinally, and carriage  13  moves between optical sensors  20 ,  21 . Optical head  15  focuses a laser beam on optical card C during the relative movement of carriage  13  to optical head  15 , thereby effecting recording or reproduction of information to optical card C. 
     In this apparatus, the mass of the moving member, which is carriage  13  or optical head  15 , is controlled to about 50 g in the maximum and to about 10 g in the minimum because of the limitation of practicable production. The mass of the whole apparatus is controlled to about 1.2 kg in the maximum in view of the portability of the apparatus and to about 0.3 kg in the minimum because of the limitation of practicable production. 
     The minimum velocity of the moving member is controlled to about 150 mm/sec for making it possible to reproduce information by irradiating optical card C with a laser beam. The maximum velocity of the moving member is controlled to about 800 mm/sec because of the mass and size of the driving motor installed in view of the portability of the apparatus. 
     The stability of the information recording-reproducing apparatus of such a construction as mentioned above was tested by 20 operators. As a result, results shown in the following Table 1 were able to be obtained. In the table, the row represents a velocity X (mm/sec) of continuous reciprocative movement of carriage  13 , and the column represents a movement distance Y (mm) of the center of gravity in the whole apparatus. In the test, the apparatus was ranked as C where the number of operators who felt the vibration of the apparatus was ten or more, B where the number of operators who felt so was not less than four, but less than ten, or A where the number of operators who felt so was not more than three. 
     
       
         
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 X 
               
             
          
           
               
                   
                 Y 
                 150 
                 300 
                 450 
                 600 
                 800 
               
               
                   
                   
               
               
                   
                 0.6 
                   
                   
                   
                   
                 A 
               
               
                   
                 0.7 
                   
                   
                   
                   
                 A 
               
               
                   
                 0.8 
                   
                   
                   
                   
                 B 
               
               
                   
                 0.9 
                   
                   
                   
                   
                 C 
               
               
                   
                 1.0 
                   
                   
                   
                   
                 C 
               
               
                   
                 1.5 
                   
                   
                   
                 A 
               
               
                   
                 1.6 
                   
                   
                   
                 A 
               
               
                   
                 1.7 
                   
                   
                   
                 B 
               
               
                   
                 1.8 
                   
                   
                   
                 C 
               
               
                   
                 1.9 
                   
                   
                 A 
               
               
                   
                 2.0 
                   
                   
                 A 
               
               
                   
                 2.1 
                   
                   
                 A 
               
               
                   
                 2.2 
                   
                   
                 B 
               
               
                   
                 2.3 
                   
                 A 
                 C 
               
               
                   
                 2.4 
                   
                 A 
               
               
                   
                 2.5 
                   
                 B 
               
               
                   
                 2.6 
                   
                 B 
               
               
                   
                 2.7 
                   
                 C 
               
               
                   
                 2.9 
                 A 
               
               
                   
                 3.0 
                 A 
               
               
                   
                 3.1 
                 B 
               
               
                   
                 3.2 
                 B 
               
               
                   
                 3.3 
                 C 
               
               
                   
                   
               
             
          
         
       
     
     When Table 1 is graphed, a graph illustrated in FIG. 4 is obtained. From Table 1 and FIG. 4, a characteristic line can be obtained by connecting a point where the moving velocity X is 150 mm/sec and the movement distance Y of the center of gravity is 3.0 mm and a point where the moving velocity X is 800 mm/sec and the movement distance Y of the center of gravity is 0.8 mm, by a straight line. This characteristic line can be expressed by a numerical formula as follows: 
     
       
           Y={( 0.8−3.0)/(800−150)} X +3.5 
       
     
     Accordingly, when the apparatus is designed so as to satisfy the following relationship: 
     
       
           Y&lt;{( 0.8−3.0)/(800−150)} X +3.5,  
       
     
     the stability and operability of the apparatus upon operation with the apparatus held in an operator&#39;s hand become the best, and as a result the apparatus is prevented from falling from the operator&#39;s hand. When the mass of the whole apparatus is controlled to 1.2 kg or lighter, the portability of the apparatus is not impaired. 
     The second embodiment of the present invention, in which the construction of the apparatus is defined from a different point of view from the first embodiment, will hereinafter be described. The information recording-reproducing apparatus according to the second embodiment also has exactly the same construction as that shown in FIG.  3 . 
     As described above, in such an information recording-reproducing apparatus as illustrated in FIG. 3, mass m 1  of a moving member, which is carriage  13  or optical head  15 , is controlled to about 50 g in the maximum and to about 10 g in the minimum because of the limitation of practicable production. Mass m 2  of the whole apparatus is controlled to about 1.2 kg in the maximum in view of the portability of the apparatus and to about 0.3 kg in the minimum because of the limitation of practicable production. 
     The minimum velocity of the moving member is controlled to about 150 mm/sec for making it possible to reproduce information by irradiating optical card C with a laser beam. The maximum velocity of the moving member is controlled to about 800 mm/sec because of the mass and size of the driving motor installed in view of the portability of the apparatus. 
     The stability of the information recording-reproducing apparatus of such a construction as mentioned above was tested by 20 operators. Results shown in the following Table 2 were able to be obtained. In the table, the row represents a velocity X (mm/sec) of continuous reciprocative movement of carriage  13 , and the column represents a mass ratio Z. In the second embodiment, mass ratio Z is a mass ratio m 1 /m 2  of carriage  13  to the whole apparatus. In the test, the apparatus was ranked as C where the number of operators who felt the vibration of the apparatus was ten or more, B where the number of operators who felt so was not less than four, but less than ten, or A where the number of operators who felt so was not more than three. 
     
       
         
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
             
             
               
                   
                   
               
               
                   
                 X 
               
             
          
           
               
                   
                 Z 
                 150 
                 300 
                 450 
                 600 
                 800 
               
               
                   
                   
               
               
                   
                 0.013 
                   
                   
                   
                   
                 A 
               
               
                   
                 0.014 
                   
                   
                   
                   
                 A 
               
               
                   
                 0.015 
                   
                   
                   
                   
                 B 
               
               
                   
                 0.016 
                   
                   
                   
                   
                 C 
               
               
                   
                 0.022 
                   
                   
                   
                 A 
               
               
                   
                 0.023 
                   
                   
                   
                 A 
               
               
                   
                 0.024 
                   
                   
                   
                 B 
               
               
                   
                 0.025 
                   
                   
                   
                 B 
               
               
                   
                 0.026 
                   
                   
                   
                 C 
               
               
                   
                 0.029 
                   
                   
                 A 
               
               
                   
                 0.030 
                   
                   
                 A 
               
               
                   
                 0.031 
                   
                   
                 B 
               
               
                   
                 0.032 
                   
                   
                 C 
               
               
                   
                 0.033 
                   
                   
                 C 
               
               
                   
                 0.037 
                   
                 A 
               
               
                   
                 0.038 
                   
                 A 
               
               
                   
                 0.039 
                   
                 B 
               
               
                   
                 0.040 
                   
                 B 
               
               
                   
                 0.044 
                 A 
               
               
                   
                 0.045 
                 A 
               
               
                   
                 0.046 
                 B 
               
               
                   
                 0.047 
                 B 
               
               
                   
                 0.048 
                 C 
               
               
                   
                   
               
             
          
         
       
     
     When Table 2 is graphed, a graph illustrated in FIG. 5 is obtained. From Table 2 and FIG. 5, a characteristic line can be obtained by connecting a point where moving velocity X is 150 mm/sec and mass ratio Z is 0.045 mm and a point where moving velocity X is 800 mm/sec and mass ratio Z is 0.014, by a straight line. This characteristic line can be expressed by a numerical formula as follows: 
     
       
           Z={( 0.014−0.045)/(800−150)} X +0.052 
       
     
     Accordingly, when the apparatus is designed so as to satisfy the following relationship: 
     
       
           Z&lt;{( 0.014−0.045)/(800−150)} X +0.052, 
       
     
     the stability and operability of the apparatus upon operation with the apparatus held in an operator&#39;s hand become the best, and as a result the apparatus is prevented from falling from the operator&#39;s hand. When mass m 2  of the whole apparatus is controlled to 1.2 kg or lighter, the portability of the apparatus is not impaired. 
     FIG. 6 is a fragmentary sectional view illustrating an information recording-reproducing apparatus according to the third embodiment of the present invention. In this embodiment, the apparatus has the same construction as the apparatus shown in FIG. 3 except that a balance weight  22  is attached to belt  18 . Therefore, in FIG. 6, like reference numerals are given to the same members as those illustrated in FIG. 3, and detailed descriptions thereof are omitted. 
     Mass m 3  of balance weight  22  is adjusted so as to be lighter than mass m 1  of carriage  13 , and balance weight  22  is fixed to the lower stage of belt  18 , thereby making it possible to move balance weight  22  in a direction opposite to the moving direction of carriage  13 . 
     The stability of the information recording-reproducing apparatus of such a construction was tested in the same manner as in the second embodiment. As a result, exactly the same results as those shown in Table 2 were able to be obtained. However, moving velocity X of the row was the same as in Table 2, but mass ratio Z of the column was defined as a mass ratio (m 1 −m 3 )/m 2  obtained by subtracting a mass ratio m 3 /m 2  of the balance weight to the whole apparatus from a mass ratio m 1 /m 2  of carriage  13  to the whole apparatus. 
     Accordingly, the same characteristic line and numerical formula as those in the second embodiment can also be obtained in the third embodiment. When the apparatus is designed so as to satisfy the following relationship: 
     
       
           Z&lt;{( 0.014−0.045)/(800−150)} X +0.052,  
       
     
     the same effect as in the second embodiment can be achieved. 
     Since mass m 3  of balance weight  22  is adjusted so as to be lighter than mass m 1  of carriage  13  in this case, the driving motors for driving carriage  13  and balance weight  22  can be held down to that small in size and light in weight, and so the portability of the apparatus is not impaired. 
     In the above-described first to third embodiments, the combination of optical card C and optical head  15  has been described. However, the present invention is not limited to this combination. Accordingly, even when an information recording medium of any other card form, for example, a magnetic card is used in place of optical card C, and a magnetic head is used in place of optical head  15 , the same effect can be achieved. 
     In the first to third embodiments, the construction that the carriage is moved in a direction parallel to the extending direction of the information tracks has been adopted. However, a construction that the head is moved in a direction parallel to the extending direction of the information tracks may also be adopted in place of the above construction.