Abstract:
A data recording device and a camera device in which, while using a disc drive not employing tracking servo, destruction of recorded data is prevented against an impact applied during data recording. The data recording device or a camera device includes a recording unit  32  for recording data on the disc-shaped recording medium without employing tracking servo provided in the inside of a casing, an acceleration sensor  33  for detecting an impact applied to the casing and a control unit  28, 31, 36  for controlling the recording unit for discontinuing data recording on the disc-shaped recording medium if an impact exceeding a pre-set value is detected based on detection results from the acceleration sensor  33.  By discontinuing data recording on the disc-shaped recording medium on detection by the acceleration sensor  33  of an impact exceeding a pre-set value, it becomes possible to prevent destruction of recorded data on the disc-shaped recording medium and failure in recording.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a data recording apparatus and a camera apparatus used with advantage for digitizing and recording a picture. 
     2. Related Art 
     There have recently investigated using a so-called removable disc-shaped recording medium in electronic apparatus for data recording/reproduction. The portable electronic apparatus are subjected during its use to external force such as vibrations or impacts or to abrupt changes in temperature or humidity. In portable electronic apparatus used under these hostile environments, there are occasions wherein the disc drive for recording/reproducing data on or from the loaded disc-shaped recording medium is loaded such that data cannot be recorded/reproduced in accordance with the pre-set format due to the above-mentioned extraneous factors. 
     In the portable electronic apparatus in particular, there are occasions wherein strong impacts are instantaneously applied from outside to the casing during use thus causing so-called detracking of the recording head. Therefore, means must be provided for preventing data already recorded in neighboring tracks of the disc-shaped recording medium from being eroded during data recording by the detracking or preventing failure in data writing in the current track. 
     In a hard disc drive, for example, there is formed a servo pattern on the hard disc surface, such that detracking is found to have occurred as a result of disengagement of the tracking servo. Thus, the device itself can inherently detect such detracking. 
     However, if a disc drive not employing tracking servo such as a floppy disc drive is used in the portable electronic apparatus, it is problematic the device itself can not inherently detect such detracking. 
     If, in the floppy disc drive, the magnetic head is deviated in an amount exceeding approximately 60 μm, data already recorded on the neighboring track of the loaded floppy disc is affected by this head deviation. In a majority of cases, this phenomenon is known to occur if a strong impact is applied to the floppy disc drive from outside. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a portable data recording apparatus in which, while using a disc drive not employing tracking servo, destruction of the recorded data or recording failure can be prevented against impacts induced during data recording. 
     It is another object of the present invention to provide a camera apparatus in which, while using a disc drive not employing tracking servo, destruction of the recorded data or recording failure can be prevented against impacts induced during data recording. 
     In one aspect, the present invention provides a portable data recording device for recording data on a disc-shaped recording medium including recording means for recording data on the disc-shaped recording medium without employing tracking servo provided in the inside of a casing, an acceleration sensor for detecting an impact applied to the casing and control means for controlling the recording means for discontinuing data recording on the disc-shaped recording medium if an impact exceeding a pre-set value is detected based on detection results from the acceleration sensor. 
     By discontinuing data recording on the disc-shaped recording medium on detection by the acceleration sensor of an impact exceeding a pre-set value, it becomes possible to prevent destruction of recorded data on the disc-shaped recording medium or failure in recording. 
     In another aspect, the present invention provides a camera device for recording data on a disc-shaped recording medium including recording means for recording data on the disc-shaped recording medium without employing tracking servo provided in the inside of a casing, an acceleration sensor for detecting an impact applied to the casing and control means for controlling the recording means for discontinuing data recording on the disc-shaped recording medium if an impact exceeding a pre-set value is detected based on detection results from the acceleration sensor. 
     By discontinuing data recording on the disc-shaped recording medium on detection by the acceleration sensor of an impact exceeding a pre-set value in the camera device of the present invention, it becomes possible to prevent destruction of recorded data on the disc-shaped recording medium or failure in recording. Thus, in the portable recording device employing a disc drive devoid of tracking servo, the recorded data can be protected against impact, while the failure of recording can be eliminated. 
     Moreover, by discontinuing data recording on the disc-shaped recording medium on detection by the acceleration sensor of an impact exceeding a pre-set value in the camera device of the present invention, it becomes possible to prevent destruction of recorded data on the disc-shaped recording medium and failure in recording. Thus, in the camera device employing a disc drive devoid of tracking servo, the recorded data can be protected against impact, while the failure of recording can be eliminated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view from the front side for illustrating the structure of the digital camera apparatus embodying the present invention. 
     FIG. 2 is a perspective view from the back side for illustrating the structure of the digital camera apparatus. 
     FIG. 3 is a block diagram for illustrating the circuit structure of the digital camera device. 
     FIG. 4 is similarly a block diagram for illustrating the circuit structure of the digital camera device. 
     FIG. 5 is an exploded perspective view for illustrating the mechanical structure of the digital camera apparatus. 
     FIG. 6 is a diagrammatic view showing the mounting angle on the circuit substrate of an acceleration sensor. 
     FIG. 7 illustrates the mounting state of the circuit substrate and the floppy disc drive on the chassis looking from a cartridge inserting opening. 
     FIG. 8 is a see-through perspective view for illustrating the structure of the acceleration sensor. 
     FIG. 9 illustrates the operation of the acceleration sensor in case of impact application. 
     FIG. 10 illustrates the structure of a magnetic head arranged in the inside of the casing of the floppy disc drive. 
     FIG. 11 is a timing chart for illustrating the operation of the acceleration sensor, flip-flop, AND gate, micro-computer and the floppy disc and the processing of recorded data. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to the drawings, preferred embodiments of the present invention will be explained in detail. A digital camera device  1 , embodying the present invention, is of a portable size and a substantially parallelepipedic shape, as shown in FIG. 1 showing the appearance of the device from the front side. In the present digital camera device  1 , a shutter button  3 , an objective lens  4  and a flash device  5  are mounted on an upper portion of a casing  2 . The shutter button  3  can be pressed with an index finger of the user&#39;s right hand. 
     On a lateral surface  6  of the casing  2  of the digital camera device  1  is mounted an opening/closing lid  7 . From the lateral surface  6 , a floppy disc cartridge  8  holding a floppy magnetic disc  9  of the size of 3.5 inch can be loaded into the inside of the casing  2 . This floppy magnetic disc  9  is referred to herein simply as a magnetic disc  9 . Specifically, as shown in FIG. 2 showing the appearance from the back side of the digital camera device  1 , there is arranged in the inside of the casing  2  a floppy disc drive  32  which will be explained subsequently in detail. The floppy disc cartridge  8  is inserted via a cartridge inserting opening  32   a  of the floppy disc drive  32  from the side of a shutter  8   a.    
     On the back side of the casing  2  of the digital camera device  1  is mounted a Liquid Crystal Display panel (LCD panel)  11  on which an object is displayed during photographing. If, in the digital camera device  1 , the object is photographed by pressing the shutter button  3 , there are recorded on a magnetic disc  9  in the floppy disc cartridge  8  loaded on the floppy disc drive  32  picture data of the object (main picture data) and thumbnail picture data operating as an index for the main picture data, 
     During reproduction of the main picture data after photographing the object, a thumbnail picture for thumbnail picture data recorded on the magnetic disc  9  is displayed for a pre-set number of pictures, such as six pictures, on the LCD display  11 . If a particular one of the thumbnail pictures is designated, the main picture data corresponding to the thumbnail picture are read out from the magnetic disc  9  so as to be displayed n the LCD panel  11 . 
     The digital camera device  1  can erase unneeded main picture data and the thumbnail picture data recorded on the magnetic disc  9  or change the arraying manner of the thumbnail pictures displayed on the LCD panel  11 , by way of a variety of editing operations. 
     That is, in the present digital camera device  1 , a variety of actuating buttons/switches  12   a,    12   b,    12   c,    12   d,    12   e,    12   f  and  12   g  are arranged around the LCD panel  11 . By actuating these operating buttons, zooming during photographing, designation of particular thumbnail pictures during reproduction or data erasure can be performed by way of editing operations. 
     The opening/closure of the opening/closing lid  7  can be achieved by vertically moving an opening/closure actuator  13  for canceling or holding the engaged state of engagement pawls  14   a,    14   b  interlocked with the opening/closure actuator  13  with engagement portions  7   a,    7   b  of the opening/closing lid  7 . 
     The circuit configuration of the digital camera device  1  is hereinafter explained. Referring to FIG. 3, the present digital camera device  1  includes a CCD  21 , as a photographing element, a sample-and-hold/analog-to-digital conversion circuit, abbreviated hereinafter to a sample-and-hold circuit  22 , a camera signal processing circuit  23 , a DRAM  24  and a DRAM controller  25 . The digital camera device  1  also includes a panel signal processing circuit  26  for furnishing RGB signals to the LCD panel  11 , an actuating input unit  27 , a micro-computer  28 , a floppy disc controller or FDC  31  and the floppy disc drive or FDD  32 , already explained with reference to FIG.  2 . The digital camera device  1  also includes a flash memory  29  as an additional constituent element. The DRAM  24 , DRAM controller  25 , micro-computer  28 , flash memory  29  and the FDC  31  are interconnected over a common bus. 
     In the digital camera device  1 , light rays from an object are passed through the objective lens  4  and received by the CCD  21  so as to be thereby converted into electrical signals. An output signal from the CCD  21  is sample-held by the sample-and-hold circuit  22  and subsequently converted by A/D conversion into 10-bit digital signals. The converted 10-bit signals are sent to the camera signal processing circuit  23 . 
     The camera signal processing circuit  23  processes the 10-bit digital signals supplied from the sample-and-hold circuit  22  in a pre-set manner to output the processed signals to the DRAM controller  25 . The camera signal processing circuit  23  in the present embodiment generates 8-bit luminance signals Y and 4-bit chroma signals C from the input signal to output the signals Y and C to the DRAM controller  25 . 
     The DRAM controller  25  directly sends the luminance signals Y and the chroma signals C from the camera signal processing circuit  23  to the panel signal processing circuit  26 . If the CCD  21  is not of the tetragonal lattice structure, the camera signal processing circuit  23  forms the luminance signals Y and the chroma signals C into the signals of the tetragonal lattice structure to send the resulting signals to the panel signal processing circuit  26 , which then generates red signals R, green signals G and blue signals B from the input luminance signals Y and chroma signals C to output the R, G and B signals to the LCD panel  11 . This displays an image of the photographing object on the LCD panel  11 . 
     The DRAM controller  25  also causes the luminance signals Y and the chroma signals C from the camera signal processing circuit  23  in pre-set areas of the DRAM  24  under control from the camera signal processing circuit  23 . The DRAM  24  is made up of two 4 MB DRAMs, and thus has a storage area of 8 MBs. 
     The actuating input unit  27  detects the actuation contents of the shutter button  3  and the actuating buttons/switches  12   a  to  12   g  to output the detected signals as actuating signals to the micro-computer  28 . 
     The micro-computer  28  is of the reduced instruction set computer RISC type capable of high-speed processing, and includes a read-only memory (ROM)  28   a  holding on memory the software program designed for controlling the respective blocks. The micro-computer  28  is responsive to actuating signals from the actuating input unit  27  to cause the software program in the ROM  28   a  to be executed to perform the processing such as picture compansion or file management during the photographing, reproduction and editing. 
     Specifically, the micro-computer  28  causes the luminance signals Y and the chroma signals C to be stored during photographing of an object in a pre-set area of the DRAM  24  from the DRAM controller  25  in order to compress the stored luminance signals Y and chroma signals C in accordance with the JPEG (Joint Photographic Coding Experts Group) system. The micro-computer  28  also causes the data compressed in accordance with the JPEG system to be written in an area different from the above-described area of the DRAM  24  as JPEG stream data. The micro-computer  28  also causes JPEG stream data to be read out from the DRAM  24  to convert the JPEG stream data into MOS-DOS (Microsoft Disc Operating System, a trademark owned by Microsoft Inc.) format data to supply the converted data to the FDC  31 . The micro-computer  28  controls the FDC  31  in order to write the data converted into the MS-DOS format data on a magnetic disc  9  of the floppy disc cartridge  8  loaded on the floppy disc drive  32 . 
     The flash memory  29  is used for storage of the version-up program in case of version-up of the function of the digital camera device  1 , and represents an additional constituent element in the present embodiment. 
     Moreover, the digital camera device  1  includes an acceleration sensor  33  for detecting the impact from outside, an amplification circuit  34  for amplifying an output signal from the acceleration sensor  33  and a flip-flop  35  for setting an output signal from the amplification circuit  34 , as shown in FIG.  4 . The acceleration sensor  33  outputs a detection signal in case of detection of an impact exceeding a pre-set G-value in a manner as will be explained in detail subsequently. 
     An output of the flip-flop  35  is supplied not only to the micro-computer  28  but also to the floppy disc drive  32  via one of input terminals of an AND gate  36 . The micro-computer  28  also outputs a reset signal to the flip-flop  35 . 
     The AND gate  36  has its opposite side input terminal connected to an output side of the FDC  31  for control signals and has its output terminal connected to the floppy disc drive  32  so as to perform the function as a gate (W gate) for issuing a permit/non-permit command for the recording operation by the floppy disc drive  32 , as shown in FIG.  4 . The acceleration sensor  33  will be explained in detail subsequently. 
     The internal mechanical structure of the digital camera device  1  is now explained. Referring to FIG. 5, the casing  2  of the digital camera device  1  can be exploded into a front side half  2   a  and a rear side half  2   b.  In these front and rear side halves  2   a  and  2   b  are arranged a circuit substrate  41 , a chassis  42  and the floppy disc drive  32  as explained with reference to FIG.  3 . Specifically, the circuit substrate  41 , chassis  42  and the floppy disc drive  32  are in the form of substantially co-extensive rectangles and arranged in the inside of the casing  2  so that the rectangles overlap with one another. 
     More specifically, the circuit substrate  41  has its four corners secured by plural set screws  43  on one of the major surfaces of the chassis  42  facing the front side half  2   a,  as shown in FIG.  5 . Also, the floppy disc drive  32  is mounted via four buffer members  45 ,  46 ,  47  and  48  for facing the opposite side major surface of the chassis  42  facing the rear side half  2   b.  The chassis  42 , carrying the circuit substrate  41  and the floppy disc drive  32 , is secured to the front side half  2   a  of the casing  2  by set screws  44  from the upper side and from the lateral side by set screws, not shown. 
     The circuit substrate  41  is substantially rectangular in shape in its entirety and has a variety of chips, such as LSIs, operating as blocks of the circuit shown in FIGS. 3 and 4. On the major surface  41   a  of the circuit substrate  41  facing the rear side half  2   b  is mounted the acceleration sensor  33  having a substantially rectangular profile, as shown in FIG. 6, the acceleration sensor  33  is as explained with reference to FIG.  4 . Specifically, the acceleration sensor  33  is mounted at an approximately lower rightward side of the major surface  41   a  of the circuit substrate  41  so that the long side of a substantially rectangular casing  61  is at an angle of approximately 45° relative to a lower side  41   b  of the circuit substrate  41 , as shown in FIG.  6 . The acceleration sensor  33  will be explained further in detail subsequently. 
     The chassis  42  is molded from metal, such as stainless steel, and has its major surface  42   a  recessed significantly. An upper flange  42   b,  a lower flange  42   c  and a side flange  42   d  are formed from the upper edge, lower edge and the right-side edge (FIG. 5) of the major surface  42   a  of the chassis  42 , respectively, in a direction facing the rear side half  2   b.    
     The floppy disc drive  32  is of a thin type f a so-called ½ height having a casing  32  of metal. This floppy disc drive  32  is mounted on the chassis  42  by set screws via the four buffer members  45 ,  46 ,  47  and  48 . Specifically, the upper flange  42   b  and the lower flange  42   c  of the chassis  42  and the buffer members  45  to  48  are provided with bores adapted to be passed through by set screws  49  to  52 . These set screws  49  to  52  are passed through these bores and screwed into tapped holes formed in the corresponding positions of the floppy disc drive  32  for securing the floppy disc drive  32  to the chassis  42 . 
     Referring to FIG. 7, showing the mounting state of the circuit substrate  41  and the floppy disc drive  32  to the chassis  42  looking from the side of the cartridge inserting opening  32   a,  the casing  32   b  of the floppy disc drive  32  is not directly contacted with the major surface  42   a  of the chassis  42 , such that the vibrations or impacts applied to the chassis  42  are transmitted via the buffer members  45  to  48  to the floppy disc drive  32 . As for the relation between the chassis  42  and the circuit substrate  41 , since the circuit substrate  41  has its four corners secured to the major surface  42   a  of the chassis  42  by set screws  43 , the vibrations or impacts applied to the chassis  42  are directly transmitted to the circuit substrate  41 . 
     The buffer members  45  to  48  function to delay the time which elapses until the impact applied to the casing  2  from outside is transmitted to the floppy disc drive  32 , and are formed of a relatively soft material, such as rubber, sponge, silicon or soft plastics. The buffer members  45  to  48  also function to weaken the impact applied to the casing  2  to some extent to transmit the thus weakened impact to the floppy disc drive  32 . 
     In the present embodiment, the floppy disc drive  32  and the casing  2  are interconnected via the chassis  42 . Alternatively, the floppy disc drive  32  and the casing  2  may also be interconnected without interposition of the chassis  42 . In this case, it suffices if the casing  2  is provided with bores for traversing by the set screws  49  to  52  and the floppy disc drive  32  is mounted on the casing via the buffer members  45  to  48  by inserting the set screws  49  to  52  into these bores. 
     Referring to the see-through perspective view of FIG. 8, an impact detection plate  62  for detecting the impact is arranged in the inside of the casing  61  of the acceleration sensor  33 . This impact detection plate  62  is substantially rectangular in profile in its entirety. Specifically, the impact detection plate  62  is formed as a thin girder by two piezoelectric ceramic plates  62   a,    62   b  having electrodes at mid positions on its major surface, as shown in FIG.  9 . The impact detection plate  62  has its longitudinal ends secured within the casing  61  and has the mid portions of the major surface thereof movable within the casing  61 . Thus, if an impact is applied in the in-plane direction of the impact detection plate  62 , this impact detection plate  62  is warped arcuately to issue a signal proportionate to the intensity of the applied impact. 
     This impact detection plate  62  is arranged in the inside of the casing  61  so that its long sides are parallel to the long side of the casing  61  and so that its both major surfaces are inclined at an angle of 45° to the bottom surface  63  of the casing  61 , as shown in FIG.  8 . The bottom surface  63  represents the attachment surface to the circuit substrate  41 . 
     By mounting the acceleration sensor  33  so that the long side of the casing  61  is inclined 45° relative to the lower side  41   b  of the major surface  41   a  of the circuit substrate  41 , as shown in FIG. 6, impacts applied from a variety of directions can be detected. Meanwhile, it has been confirmed experimentally that, by mounting the acceleration sensor  33  at this angle, impact detection signals of a uniform strength an be obtained without regard to the direction of application of the impacts. That is, in the digital camera device  1 , since the acceleration sensor  33  is mounted so that the major surface of the impact detection plate  62  of the acceleration sensor  33  will be approximately at an angle of 45° relative to the three axes X, Y and Z shown in FIG. 5 in case the casing  2  is used in the basic position shown in FIGS. 1 and 2, the impacts from the axial directions of X, Y and Z can be detected uniformly, such that a sufficient function can be manifested by a sole acceleration sensor. 
     FIG. 10 shows the mechanism around a magnetic head arranged in a casing  32   b  of the floppy disc drive  32 . Within the casing  32   b  of the floppy disc drive  32  is mounted a head actuator  70 , as shown in FIG.  10 A. This head actuator  70  includes a head arm  73  formed as-one with upper and lower arm members  71 ,  72 , upper and lower magnetic heads  74  ( 74   a,    74   b ) mounted on the distal ends of the arm members  71 ,  72 , a feed motor  75  for moving the head arm  73  and a feed screw  76  mounted on a rotor of the feed motor  75 . The head actuator  70  also includes a pin  77  mounted on the distal end of the arm member  73  for engagement with a spiral groove  76   a  formed in the feed screw  76  and a guide shaft  79  mounted in a through-hole  78  formed in the arm member  72  for guiding the movement of the head arm  73 . 
     The arm members  71 ,  72  are molded from, for example, synthetic resin, and has upper and lower paired magnetic heads  74 ,  74  at the distal ends thereof, these magnetic heads being positioned on both sides of the major surfaces of the magnetic disc  9 , as shown in FIG.  10 B. Although not shown, a spindle motor for rotationally driving the magnetic disc  9  is mounted below the mid position of the major surface of the magnetic disc  9 . 
     With the above-described head actuator  70 , the magnetic head  74  is slid against the major surface of the magnetic disc  9 , run in rotation by the spindle motor, for applying a magnetic field on the recording track of the magnetic disc or detecting magnetic signals recorded on the recording track of the magnetic disc in order to record or reproduce main picture data or thumbnail picture data. 
     The head arm  73  of the head actuator  70  is reciprocated along a guide shaft  79  in the radial direction of the guide shaft  79 , that is in the direction indicated by arrow in FIGS. 10A and 10B. Specifically, when the feed motor  75  is rotated a pre-set rotational angle, the head arm  73  is moved track-by-track on the recording tracks formed on the magnetic disc  9 . If a strong impact is applied to the floppy disc drive  32  in its entirety, the casing  32   b  or the head arm  73  is flexed to cause position offset of the magnetic heads  74   a,    74   b  relative to the recording track of the magnetic disc  9 , or failure in contact, thus causing erosion of neighboring tracks during data recording or otherwise causing failure in writing on the current track. 
     In the case of the 3.5 inch ½ height floppy disc drive, as described above, it has been found by experiments that the G-value of occurrence of writing errors for the current recording tracks is 3 G to 12 G, with the G-value of occurrence of the erosion to the neighboring tracks being not less than 50 G. It is therefore reasonable to select the setting value for impact detection of the acceleration sensor  33  to not less than approximately 50 G for preventing erosion to the neighboring tracks and to select the setting value for impact detection of the acceleration sensor  33  to a suitable value ranging between 3 and 12 G for preventing error occurrence for the current track as well. It has been found by experiments that an optimum result can be obtained with the present digital camera device  1  by selecting the setting value for impact detection of the acceleration sensor  33  to 7 G to 8 G, in particular to approximately 8 G. 
     The operation of the acceleration sensor  33  and the floppy disc drive  32  in case an impact is applied to the casing  2  of the digital camera device  1  from outside is no explained with reference to FIG.  11 . 
     In the digital camera device  1 , the track number and the sector number on the magnetic disc  9  for recording are set by the micro-computer  28  shown in FIG. 4 prior to proceeding to recording respective data. The track number is herein set to n. The micro-computer  8  then controls the FDC 31  to move the magnetic head  74  to the track and sector positions by way of the seek operation. 
     At a time point t 0  corresponding to the end of the seek operation, the micro-computer  28  outputs a reset signal to the flip-flop  35  to reset the output of the flip-flop  35 , at the same time as a control signals is outputted from the FDC  31  to invert the output signal of the AND gate  36  to permit the data recording in the FDD  32 . 
     Then, recording data is supplied from the FDC  31  to the floppy disc drive  32  to supply the recording current to the magnetic head  74  so that recording data is written on pre-set sectors of the track n as from time t 1 . The time between t 0  and t 1  stands for the rise time until coming into operation of the floppy disc drive  32 . 
     If an impact exceeding e.g., 8 G is produced at time t 2 , this impact is sequentially transmitted from the casing  2  via chassis  42 , circuit substrate  41  and the acceleration sensor  33 , which then outputs an impact detection signal. This detection signal from the acceleration sensor  33  is amplified by the amplification circuit  34  and thence supplied to the flip-flop  35  to invert the output thereof. The inverted output signal of the flip-flop  35  is sent to the micro-computer  28  and to the AND gate  36 . This complements the output signal of the AND gate  36  to close the gate of the control signals from the FDC  31  for the floppy disc drive  32 . Thus, the control current ceases to be supplied as from time t 2  to the recording head  74  of the floppy disc drive  32 . 
     Since the chassis  42  and the floppy disc drive  32  are interconnected via buffer members  45  to  48  adapted for delaying the impact transmission, this impact is transmitted at a timing delayed from the transmission timing to the acceleration sensor  33 , herein a pre-set timing delayed from time t 2 . Since no recording current is supplied at this timing to the magnetic head  74  of the floppy disc drive  32 , it becomes possible to prevent erosion to neighboring tracks or failure in writing in the current track even on occurrence of detracking of the magnetic head  74  by impacts. 
     That is, in the present embodiment, since the time when the impact applied to the casing  2  is transmitted to the floppy disc drive  32  can be retarded, the impact applied to the acceleration sensor  33  can be relatively quickened thus compensating for the time delay required for interrupting the recording current. In particular, if the casing  2  or the chassis  42  is of high tenacity, the speed at which the impact is transmitted to the magnetic head  74  of the floppy disc drive  32  is increased significantly, such that the recording current interruption after detection of the acceleration sensor  33  cannot be achieved in time. In such case, it is highly effective to interconnect the floppy disc drive  32  and the casing  2  with interposition of the buffer members  45  to  48  since the impact transmission timing can then be retarded to permit the function of the acceleration sensor  33  to be performed more effectively. 
     It has been confirmed experimentally that, in the present embodiment, the time until the impact applied to the casing  2  is transmitted to the floppy disc drive  32  is 11 msec±5 msec. 
     If an output signal of the flip-flip  35 , complemented on occurrence of the impact, is fed to the micro-computer  28  at time t 2 , the micro-computer  28  outputs a control signal to the FDC  31  to move the magnetic head  74  to an original track of the track n by way of re-seeking control. 
     At a time t 3  when the re-seeking comes to a close, a reset signal is outputted to the flip-flop  35 . The output signal of the flip-flop  35  is complemented at time t 4  corresponding to the decay time of the reset signal, this complemented signal being sent to the micro-computer  28  and to the AND gate  36 . By the complemented output signal being sent to the AND gate  36 , the output signal of the AND gate  36  is complemented at this time t 4  to open the gate to permit data recording by the floppy disc drive  32 . 
     The micro-computer  28  then controls the FDC  31  to supply the recording data from the FDC  31  to the floppy disc drive  32 , with the recording data as from the recording start time t 1  as the re-trial data. This furnishes the recording current for the re-trial data to the recording head  74  of the floppy disc drive  32  as from time t 5 , as shown in FIG. 11, thus causing the recording data to be written as from the preset sector of the track n. Meanwhile, the time interval since time t 4  until time t 5  is the rise time until actuation of the floppy disc drive  32 .