Abstract:
A data storage device is provided. At least a storage section configured to store information therein and a connection terminal configured to transmit information are mounted on a substrate. A casing accommodates the substrate, the casing is formed with an opening to expose a connection portion of the connection terminal to the outside. A shield plate configured to shield the opening of the casing. A shield plate actuation mechanism is configured to detect a connection state between the connection terminal and a receiving terminal to which the connection terminal is connected and actuate the shield plate. The shield plate actuation mechanism actuates the shield plate to shield the opening when the shield plate actuation mechanism detects that the connection terminal is separated from the receiving terminal.

Description:
[0001]    The disclosure of Japanese Patent Application No. 2009-276145 filed on Dec. 4, 2009, including specification, drawings and claims are incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    The present invention relates to a data storage device which stores data regarding accounting in the field of sales, logistics, commercial distribution, and the like, and a printing apparatus including the data storage device. 
         [0003]    In the field of sales, logistics, and commercial distribution, various systems (a POS system and the like) are used which process accounting information. In such a system, a printer is used as a printing apparatus so as to record and issue accounting information. As this type of printer, there is a so-called fiscal printer. The fiscal printer includes a printing main body section which records and issues accounting information, and a data storage device which stores the recorded accounting information. Data which is stored in the data storage device relates to, for example, tax and is used to secure taxation. 
         [0004]    Thus, it is desirable that the data storage device has a structure in which data based on accounting information cannot be falsified. For this reason, it is necessary to prevent disconnection of a substrate or a memory for data falsification or unauthorized access to data. A sealed structure is proposed in which a substrate, on which an electronic component such as a memory for storing data is mounted, is accommodated in a cover (casing), a wire is locked to a screw fastening the cover, and the wire is sealed (for example, see Patent Document 1). 
         [0005]    Patent Document 1: JP-A-2007-24291 
         [0006]    In recent years, a data storage device is accommodated in a casing and managed with a unique number as a single product. This type of data storage device is detachably attached to a fiscal printer main body section by connection terminals or the like. For this reason, it is anticipated that the data storage device will be unauthorizedly disconnected for data falsification or unauthorized access to data. Accordingly, there is a demand for retaining the history and trace of disconnection, making it impossible for unauthorized access to an electronic component, such as a memory, and making it impossible for reconnection after data falsification. 
       SUMMARY 
       [0007]    It is therefore an object of at least one embodiment of the present invention to solve at least one of the above-described problems and the present invention can be implemented as the following aspects or application examples. 
         [0008]    In order to achieve at least one of the above-described objects, according to a first aspect of the embodiments of the present invention, there is provided a data storage device, comprising: a substrate on which at least a storage section configured to store information (data) therein and a connection terminal configured to transmit information are mounted; a casing accommodating the substrate, the casing formed with an opening to expose a connection portion of the connection terminal to the outside; a shield plate configured to shield the opening of the casing; and a shield plate actuation mechanism configured to detect a connection state between the connection terminal and a receiving terminal to which the connection terminal is connected and actuate the shield plate, wherein the shield plate actuation mechanism actuates the shield plate to shield the opening when the shield plate actuation mechanism detects that the connection terminal is separated from the receiving terminal. 
         [0009]    With this structure, when the data storage device is disconnected, that is, when the connection terminal of the data storage device is separated from the receiving terminal, the shield plate which is actuated by the shield plate actuation mechanism can shield a part or the entire part of the opening which exposes the connection portion of the connection terminal. For this reason, it is possible to prevent unauthorized access from a terminal section of the connection terminal. The disconnection is found because the opening is shielded, and reconnection to the receiving terminal is impossible. For this reason, it is possible to prevent illegality. 
         [0010]    In the data storage device, the shield plate actuation mechanism may include: the shield plate; an urging member that urges the shield plate in one direction; a first shield plate locking member that locks the movement of the shield plate; and a second shield plate locking member that releases locking of the first shield plate locking member and locks the movement of the shield plate when the shield plate actuation mechanism detects that the connection terminal is separated from the receiving terminal. 
         [0011]    In the data storage device, the second shield plate locking member may be provided at a side of the receiving terminal. 
         [0012]    With this structure, when the data storage device is in an initial state, that is, in a state where the connection terminal of the data storage device is not connected to the receiving terminal, the shield plate is locked to the first shield plate locking means, and the connection terminal of the opening is exposed without being shielded. If it is detected that the connection terminal of the data storage device is connected to the receiving terminal, the locking of the first shield plate locking means is released, and the shield plate which is urged by the urging means is locked by the second shield plate locking means on the receiving terminal side. If the connection terminal and the receiving terminal are separated from each other, the second shield plate locking means provided on the receiving terminal side is separated and the urged shield plate is unlocked. For this reason, the shield plate can shield the opening. 
         [0013]    According to a second aspect of the embodiments of the present invention, there is provided a printing apparatus, comprising: a printing section configured to print the information on a recording sheet; a main body section including at least the printing section; and the above-described data storage device, wherein the main body section has the receiving terminal and the data storage device is connected to the printing apparatus through the connection terminal and the receiving terminal. 
         [0014]    With this configuration, the printing apparatus can print information (accounting information) and store necessary information in a memory. When the data storage device is unauthorizedly disconnected, the connection terminal section is shielded, reducing unauthorized access and data falsification. Reconnection is impossible, suppressing illegality. 
         [0015]    In the printing apparatus, the data storage device may further comprise a control section configured to control the main body section, inside the casing. 
         [0016]    With this configuration, the data storage device has the storage section, such as a memory, and the control section of the printing apparatus main body section. That is, printing is impossible in a state where the memory is separated. For this reason, necessary information in accounting information issued as a receipt can be accurately stored in the memory. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    In the accompanying drawings: 
           [0018]      FIG. 1  is a perspective view showing the exterior configuration of a thermal printer; 
           [0019]      FIG. 2  is a perspective view of a printer mechanism section in a state where a cover frame is open; 
           [0020]      FIG. 3  is a perspective view of the printer mechanism section in a state where the cover frame is closed; 
           [0021]      FIG. 4  is a schematic side sectional view of the thermal printer; 
           [0022]      FIG. 5  is an exterior perspective view of a thermal head; 
           [0023]      FIGS. 6A and 6B  are diagrams showing the exterior of a data storage device; 
           [0024]      FIG. 7  is a block diagram showing the configuration of a data storage device and a printer main body section; 
           [0025]      FIGS. 8A to 8C  illustrate a shield plate actuation mechanism; 
           [0026]      FIGS. 9A and 9B  are diagrams illustrating the operation of the shield plate actuation mechanism; and 
           [0027]      FIG. 10  is a perspective view showing the relationship between the data storage device and the printer main body section. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0028]    Hereinafter, this embodiment will be described with reference to the drawings. In the drawings related to the following description, for convenience of description and drawing, the horizontal and vertical scale of each member or portion may be different from the actual scale. 
         [0029]    (Overall Configuration of Printing Apparatus) 
         [0030]    As a printing apparatus of this embodiment, for example, a thermal printer will be described with reference to  FIGS. 1 to 4 .  FIG. 1  is a perspective view showing the exterior configuration of a thermal printer.  FIGS. 2 and 3  are perspective views showing the exterior of a printer mechanism section. Specifically,  FIG. 2  is a perspective view of the printer mechanism section in a state where a cover frame is open.  FIG. 3  is a perspective view of the printer mechanism section in a state where the cover frame is closed.  FIG. 4  is a side sectional view of the thermal printer. 
         [0031]    The thermal printer is used as a fiscal printer which is used to print and issue accounting information on a receipt or the like and to store the accounting information as data. The thermal printer uses a roll-shaped thermal sheet as a recording sheet, and prints and issues the accounting information on the thermal sheet. From the accounting information, for example, information regarding tax is stored in a fiscal memory as fiscal data. in  FIGS. 1 to 4 , the X direction represents the width direction of the thermal sheet to be printed, the Z direction represents the sheet feed direction of the thermal sheet in a thermal head section serving as a printing head, and the Y direction represents the direction orthogonal to the X direction and the Z direction. 
         [0032]    As shown in  FIG. 4 , a thermal printer  100  includes a printer main body section  180  serving as a printing apparatus main body section and a data storage device  300 , The printer main body section  180  includes a printer mechanism section  150  and an exterior case  200 . The data storage device  300  described below is detachably connected to the printer main body section  180 . 
         [0033]    The printer mechanism section  150  shown in  FIGS. 2 to 4  is accommodated in the exterior case  200  shown in  FIG. 1 . Specifically, the printer mechanism section  150  is fixed at the upper part of a lower case  205  made of resin or the like. The lateral surface portion and the rear portion of the printer mechanism section  150  are covered with an upper case  210 , and the front portion of the printer mechanism section  150  in the Y direction is covered with a panel  215 . The top surface of the printer mechanism section  150  is covered with an upper cover  220 . The data storage device  300  is arranged at the lower part of the lower case  205  through an internal connection terminal  43  and a connector  91  serving as a receiving terminal. 
         [0034]    As shown in  FIG. 1 , an open button  230  is provided on one side in the X direction of the top surface of the upper case  210 . The open button  230  is depressed in the direction indicated by an arrow B of  FIG. 1 , such that a cover open lever  235  provided in the printer mechanism section  150  of  FIG. 3  can be rotated around a fulcrum  240 . The cover open lever  235  is combined with a locking mechanism of a cover frame  12  shown in  FIG. 2  and rotates in the clockwise direction such that the locking mechanism is released. The cover frame  12  is combined with the upper cover  220 . For this reason, the upper cover  220  is opened in the direction of an arrow C, such that a roll sheet holder  16  is exposed. That is, this state is the state shown in  FIG. 2  where the cover frame  12  of the printer mechanism section  150  is open. Thus, a roll-shaped thermal sheet S can be set or ejected. 
         [0035]    The thermal sheet S which is used in this embodiment is a roll-shaped thermal sheet S in which a printing surface has a coloring layer with a coloring agent held by a binder or the like, and the printing surfaces are sequentially laminated on the outer surface. Hereinafter, the roll-shaped thermal sheet is called a roller sheet R. 
         [0036]    (Overall Configuration of Printer Mechanism Section) 
         [0037]    The details of the printer mechanism section will be described with reference to  FIGS. 2 to 5 .  FIG. 5  is an exterior perspective view of a thermal head, The X direction and the Z direction shown in  FIG. 5  are respectively the same as the X direction and the Z direction shown in  FIGS. 1 to 4 , As shown in  FIGS. 2 to 4 , the printer mechanism section  150  includes a main body frame  60 , the cover frame  12 , the roll sheet holder  16 , a cutter section  20 , and a printing section  70 . 
         [0038]    As shown in  FIG. 2 , the main body frame  60  is formed of sheet metal or the like in a substantially box shape having openings upward in the Z direction and forward in the Y direction. The cover frame  12  is provided at the upper rear part of the main body frame  60 . The cover frame  12  is attached to be openable around support shafts  68  provided at the upper ends on both sides of the rear part of the main body frame  60 . The cover frame  12  is provided with an arc-shaped cover  15  for avoiding contact with the roller sheet R when the cover frame  12  is closed. When the installation angle of the thermal printer  100  is changed, that is, when the thermal printer  100  is placed longitudinally, the cover  15  also functions as a holding member which receives the roll sheet R. 
         [0039]    As shown in  FIG. 2 , the roll sheet holder  16  is provided to he covered with the cover frame  12  at the rear of the boxlike inside of the main body frame  60 . The roll sheet holder  16  has a substantially arc-shaped dent corresponding to the maximum diameter of the roll sheet R at its central portion. The roller sheet holder  16  is attached at the bottom of the main body frame  60  such that the lateral opening of the arc-shaped dent turns toward both lateral surfaces of the main body frame  60 . Both later portions inside the main body frame  60  function as lateral guide portions of the roll sheet R. For this reason, the roll sheet R is set such that the movement of the lateral surface in the width direction is regulated by both lateral portions inside the main body frame  60 , and the roller sheet R is rotatably held in the substantially arc-shaped dent of the roll sheet holder  16 . 
         [0040]    (Cutter Section) 
         [0041]    As shown in  FIG. 4 , the cutter section  20  is provided in front of the main body frame  60 , that is, in the vicinity of a sheet outlet port G at a position opposite the support shafts  68  of the cover frame  12 . The cutter section  20  includes a movable blade  21 , driving means  22  for the movable blade  21 , and a fixed blade  27 . The movable blade  21  and the driving means  22  are accommodated in a first cutter cover  24  and arranged on the main body frame  60  side. The movable blade  21  is reciprocated by the driving means  22  in the direction of an arrow E in the drawing. The fixed blade  27  is accommodated in a second cutter cover  29  and arranged on the cover frame  12  side, that is, on the side opposite the cover frame  12  with a transport path, through which the thermal sheet S passes, interposed between the fixed blade  27  and the cover frame  12 . For this reason, in a state where the cover frame  12  is closed, the blade portion of the movable blade  21  which is reciprocated by the driving means  22  and the blade portion of the fixed blade  27  slide in a state of being in contact with each other. Thus, the thermal sheet S is cut in the vicinity of the sheet outlet port G. 
         [0042]    (Printing Section) 
         [0043]    As shown in  FIG. 4 , the printing section  70  is provided in the vicinity of an outlet port on a transport path D of the thermal sheet S with the roll sheet holder  16  as a start point and the sheet outlet port G of the cutter section  20  as an end point. The printing section  70  has the thermal head  10 , a head holding mechanism  77 , and a platen  71 . The thermal head  10  and the head holding mechanism  77  are provided on the main body frame  60  side and the platen  71  is provided on the cover frame  12  side in a state of being separable. 
         [0044]    As shown in  FIG. 5 , the thermal head  10  has a heat release plate  106 , a head support shaft  102 , a head substrate  110  serving as a substrate, driver ICs  120 , and an FPC  108 . The head substrate  110  has a rectangular shape in which a heat generation element array  145   a  having a plurality of heat generation elements  145  is formed in the upward Z direction of the drawing along the longitudinal direction. A plurality of driver ICs  120  are provided in parallel to the heat generation element array  145   a  to drive the heat generation elements  145 . The heat release plate  106  is formed of a drawn material, such as aluminum. The head substrate  110  is adhered to a locking surface  106   a  of the heat release plate  106  by a two-sided adhesive tape or the like. 
         [0045]    Above the heat release plate  106  in the Z direction of the head substrate  110 , a guide slope portion  104  is formed along the longitudinal direction of the heat release plate  106 . When the cover frame  12  shown in  FIG. 4  is closed, the platen  71  slides along the guide slope portion  104  and is guided to a predetermined position. At this time, the inclination of the guide slope portion  104  is at a predetermined angle such that the platen  71  does not collide against the head substrate  110 . The slope of the guide slope portion  104  substantially has the same height as the head substrate  110  provided near the guide slope portion  104 . The head support shaft  102  is a columnar round pin and is pressed into holes provided at the left and right lateral portions of the heat release plate  106 . The FPC  108  has one end connected to a connection terminal (not shown) provided in the head substrate  110  and the other end connected to a relay portion  95  shown in  FIG. 4 . The relay portion  95  has a function of collecting wires of the printer main body section  180  and the like and connecting the wires and the data storage device  300 . 
         [0046]    The head holding mechanism  77  shown in  FIG. 4  includes a cutout portion  62  serving as a groove portion formed in the main body frame  60 , a head pressing plate  72 , and a spring  75  attached to the head pressing plate  72 . The cutout portion  62  has an opening upward of the main body frame  60  and is formed with a plurality of groove portions. The thermal head  10  is attached to the main body frame  60  by inserting the head support shaft  102  into a part of the cutout portion  62  of the main body frame  60 . The head pressing plate  72  is formed with bent portions at its upper and lower parts, and a spring  75  which is a compressed coil spring is fixed to the head pressing plate  72 . The head pressing plate  72  is inserted into the cutout portion  62  and attached to the main body frame  60  by engaging the bent portions with a part of the cutout portion  62 . 
         [0047]    When this happens, the thermal head  10  and the head pressing plate  72  are supported on both sides of the cutout portion  62  in a state of being substantially parallel to each other. The spring  75  fixed to the head pressing plate  72  comes into contact with the rear surface of the thermal head  10 , The spring  75  urges the thermal head  10  toward the platen  71 . The head holding mechanism  77  can be disengaged from the cutout portion  62  by displacing the spring  75  fixed to the head pressing plate  72  from the rear surface of the thermal head  10 . The urging force of the spring  75  is eliminated, thus the thermal head  10  can also be disengaged from the cutout portion  62 . Thus, the thermal head  10  is detachably supported with respect to the main body frame  60 . 
         [0048]    As shown in  FIGS. 2 and 4 , the platen  71  is formed of an elastic member, such as rubber, in a cylindrical roller shape, and is rotatably supported by the cover frame  12  through platen bearings  73 . A platen gear  74  is pressed into one shaft of the platen  71 . The main body frame  60  is provided with groove portions  64 . If the cover frame  12  is closed, the platen  71  is guided to the guide slope portion  104  (see  FIG. 5 ) of the thermal head  10  and the platen bearings  73  come into contact with the groove portions  64 . A downward force is applied to the cover frame  12  because of a pressing force of the thermal head  10  against the platen  71 , such that the position of the platen  71  is determined. 
         [0049]    With the above-described configuration, as shown in  FIG. 4 , the platen  71  presses the thermal sheet S from the inner surface S 2  of the thermal sheet S toward the thermal head  10 . The thermal head  10  which faces the platen  71  presses the thermal sheet S from the outer surface S 1  of the thermal sheet S toward the platen  71 . Thus, the thermal sheet S is sandwiched between the platen  71  and the thermal head  10 . At this time, the above-described coloring layer is formed on the outer surface S 1  of the thermal sheet S. As shown in  FIG. 2 , a sheet feed motor  66  and a sheet feed transmission gear  67  for rotating the platen  71  are provided at the lateral surface of the main body frame  60 . As described above, the platen  71  is positioned in the groove portions  64  of the main body frame  60 , such that the platen gear  74  and the sheet feed transmission gear  67  are meshed with each other and power from the sheet feed motor  66  is transmitted to the platen  71 . 
         [0050]    In the thermal printer  100  configured as above, the cover frame  12  connected to the upper cover  220  is opened, the roll sheet R which is the thermal sheet S is set, the thermal sheet S is pulled out to the sheet outlet port G, and the cover frame  12  connected to the upper cover  220  is closed. Thus, the thermal sheet S is set between the platen  71  and the thermal head  10  and between the movable blade  21  and the fixed blade  27 . The sheet feed motor  66  is activated to rotate the platen  71  and to feed the thermal sheet S. Electrical conduction is selectively provided to the heat generation elements  145  arranged linearly in the thermal head  10  to generate heat, such that predetermined information can be printed on the thermal sheet S. The cutter section  20  is driven to reciprocate the movable blade  21  with respect to the fixed blade  27 . Thus, the thermal sheet S with information printed thereon can be cut at a predetermined length and issued as a single sheet, such as a receipt. 
         [0051]    (Overall Configuration of Data Storage Device) 
         [0052]    The overall configuration of the data storage device will be described with reference to  FIGS. 6A ,  6 B, and  7 .  FIGS. 6A and 6B  are diagrams showing the exterior of the data storage device.  FIG. 6A  is a perspective view when viewed from an external connection terminal.  FIG. 6B  is a perspective view when viewed from an internal connection terminal.  FIG. 7  is a block diagram showing the configuration of the data storage device and the printer main body section. The X direction, the Y direction, and the Z direction shown in  FIGS. 6A and 6B  are respectively the same as the X direction, the Y direction, and the Z direction shown in  FIGS. 1 to 4 . 
         [0053]    The data storage device  300  of this embodiment has a substrate on which a driving circuit of the thermal printer  100  and an electronic component, such as a fiscal memory which stores accounting information as data, are mounted. The thermal printer  100  (also referred to as a fiscal printer) individually prints and issues a receipt which is delivered to a customer at the time of a commercial transaction, such as a sale, the breakdown of a receipt for a seller, or a journal on which accounting information, such as the total sales amount and the total amount per product item, is recorded. The thermal printer  100  is driven tinder the control of the driving circuit. 
         [0054]    The fiscal memory stores information regarding tax (hereinafter, referred to as fiscal data) from the accounting information. Fiscal data is used, for example, to secure taxation and, as necessary, a government inspector reads and inspects fiscal data. It is necessary that fiscal data stored in the fiscal memory cannot be falsified. For this reason, the specification of the data storage device  300  is strictly restricted in accordance with the law (fiscal law). For example, there are restrictions on prohibiting the data storage device  300  which has been connected to the printer main body section  180  from being easily separated, and on prohibiting the data storage device  300 , which has been unauthorizedly separated, from being reconnected and the like. The contents of the fiscal law and the definition of fiscal data differ between countries. 
         [0055]    As shown in  FIGS. 6A and 6B , the data storage device  300  includes a main body case  31 , a main substrate  32 , external connection terminals  42 , an internal connection terminal  43 , and a shield plate actuation mechanism  45 . The main body case  31  includes a substantially rectangular boxlike first case  33  with an opened bottom surface and a second case  34  forming the bottom surface thereof, and has a rectangular box shape. At one lateral surface  31   a  of the main body case  31  shown in  FIG. 6A , the connection portions of the external connection terminals  42  are exposed. At the other lateral surface  31   b  of the main body case  31  shown in  FIG. 6B , an opening  35  is provided and the internal connection terminal  43  is arranged behind the opening  35  such that the connection portion thereof turns outward. The shield plate actuation mechanism  45  is provided in the vicinity of the opening  35  and the connection portion of the internal connection terminal  43 . The main substrate  32  is accommodated in the main body case  31 . The details of the main substrate  32  and the shield plate actuation mechanism  45  will be described below. 
         [0056]    The law (fiscal law) demands that the main body case  31  is structured such that it is not easily disassembled and, when the main body case  31  is disassembled without permission, the history of the disassembling is retained. Although in this embodiment, there is no particular limitation, in assembling the first case  33  and the second case  34 , the first case  33  and the second case  34  may be fastened to each other by using a special tool, may be fixed to each other by using a tap having an irreversible structure, or may be fixed to and assembled with each other by a seal material or an adhesive. 
         [0057]    (Main Substrate) 
         [0058]    Next, the main substrate will be described with reference to  FIG. 7 . As shown in FIG.  7 , the main substrate  32  includes a printer control section  78 , a fiscal data processing section  80 , an external connection terminal  42 , and an internal connection terminal  43 . The printer control section  78  includes a printer control CPU (Central Processing Unit)  79 , an information processing section (not shown), a driver (not shown) which drives the thermal head or various motors, and the like. The printer control CPU  79  performs various kinds of processing, such as input signal processing from an operation section or detection section (not shown) and printing processing, to perform overall control of the printer main body section  180  (thermal printer  100 ). 
         [0059]    The fiscal data processing section  80  includes a fiscal memory  81 , an EJ (Electrical Journal) memory  82 , a fiscal control section  83 , a protect circuit  84 , an RTC (Real Time Clock)  87 , an SRAM (Static Random Access Memory)  88 , and a battery  89 . For the fiscal memory  81 , a memory, called a random ROM (Read Only Memory), is used in which data can be written into one address once only. The fiscal memory  81  stores fiscal data regarding tax, such as the total sales amount. The EJ memory  82  is an electronic journal memory and stores individual sales data by using a nonvolatile memory device, such as a NAND-type flash memory. 
         [0060]    The fiscal control section  83  includes a fiscal control CPU  85  and a programmable ROM  86 . The fiscal control CPU  85  performs overall control of the fiscal data processing section  80  and processes data, such as accounting information. The programmable ROM  86  is a device into which a programmable logic circuit is written and controls writing, reading, or the like with respect to the fiscal memory  81 . The protect circuit  84  has a function of preventing unauthorized access or falsification of data stored in the fiscal memory  81  or the EJ memory  82 . 
         [0061]    The RTC  87  is a real-time clock and is an IC which counts data and time. The SRAM  88  functions as a working memory to temporarily store various kinds of data, such as fiscal data or to temporarily expand a program of data processing or the like which is executed by the fiscal control CPU  85 . The SRAM  88  has a battery backup function and uses the battery  89  as a power source. The battery  89  also supplies electricity to the RTC  87  and counts time even in a state where the main power source is shut off. 
         [0062]    The external connection terminal  42  has a plurality of ports, connects a host computer  90 , the printer control section  78 , and the fiscal data processing section  80 , and performs transmission/reception of commands or data with the host computer  90 . The external connection terminal  42  has a fiscal port which is used only when the government inspector reads fiscal data of the fiscal memory  81 . The internal connection terminal  43  is constituted by a single connector, and is connected to a connector  91  provided in the printer main body section  180  including the printer mechanism section  150  to transmit printing data or the drive signals to various mechanisms or to receive a sensor detection signal from the printer main body section  180 . The internal connection terminal  43  includes an electronic switch (not shown). The electronic switch electrically detects that the data storage device  300  is separated from the printer main body section  180  and sends a signal to the RTC  87 . The RTC  87  obtains the time at which the signal is received, sends the result to any available memory, and stores the result in the memory. 
         [0063]    In the data storage device  300  configured as above, printing data including a command sent from the host computer  90  and accounting information is processed by the printer control section  78 , and printed on the thermal sheet S and issued as a receipt by the printer main body section  180 . In the data storage device  300 , printing data is processed by the fiscal data processing section  80  to extract necessary data from printing data and to sequentially store necessary data in the ES memory  82 . The ES memory  82  accumulates such data for each receipt. Fiscal data related to tax is selected from printing data or data which is temporarily stored in the SRAM  88  and stored in the fiscal memory  81 . At this timed, as necessary, temporal information is given by the RTC  87 . The selection and processing are controlled by the fiscal control CPU  85  using a program which is mainly stored in the programmable ROM  86 . 
         [0064]    The law (fiscal law) demands that it is possible to prohibit easy access to the fiscal memory  81  or the EJ memory  82  and, when access is made, the history of the access is retained. For this reason, the protect circuit  84  is provided in front of the fiscal memory  81  and the EJ memory  82 , and for example, access is permitted only on the basis of a permission signal sent from the fiscal control CPU  85 . The specification of the protect circuit  84  is not particularly limited. A microcomputer or a CPLD (Complex Programmable Logic Device) may be used. 
         [0065]    When the government inspector reads fiscal data of the fiscal memory  81  for inspection, for example, confidential ID information is used and a dedicated. fiscal port is used. The fiscal control CPU  85  recognizes the ID information and sends a reading permission signal of the protect signal  84  to permit access to the fiscal memory  81 . As necessary, access to the EJ memory  82  is permitted. The access history is given temporal information by the RTC  87  and stored in the fiscal memory  81 . 
         [0066]    (Shield Plate Actuation Mechanism) 
         [0067]    Next, the shield plate actuation mechanism will be described with reference to  FIGS. 8A to 10 .  FIGS. 8A to 8C  are diagrams illustrating the shield plate actuation mechanism. FIG.  8 A is a perspective view of the shield plate actuation mechanism in the initial state when viewed from the inner surface of the main body case.  FIG. 8B  is a perspective view of a plate spring serving as urging means.  FIG. 8C  is a perspective view of the periphery of the receiving terminal of the relay portion.  FIGS. 9A and 9B  are diagrams illustrating the operation of the shield plate actuation mechanism.  FIG. 10  is a perspective view showing the relationship between the data storage device and the printer main body section. The X direction, the Y direction, and the Z direction shown in  FIGS. 8A to 10  are respectively the same as the X direction, the Y direction, and the Z direction shown in  FIGS. 1 to 4 . 
         [0068]    As shown in  FIGS. 8A ,  8 B, and  8 C, the shield plate actuation mechanism  45  includes a shield plate  46 , a spring  47  serving as urging means, a shield plate guide  44 , first shield plate locking means  48 , and second shield plate locking means  49 . The shield plate actuation mechanism  45  is arranged in the periphery of the opening  35  of the inner surface  31   c  of the main body case  31 . 
         [0069]    The shield plate  46  is formed in a flat plate shape having a size such that the opening  35  of the main body case  31  is shielded. Both ends of the shield plate  46  are guided by L-shaped shield plate guides  44  arranged on both sides of the opening  35 , and the shield plate  46  is arranged to be movable in the Z direction. An upper side  46   b  of the shield plate  46  is urged by the spring  47  which is a compressed coil spring and is applied with a spring force in the Z(−) direction. A lower side  46   c  of the shield plate  46  is locked to a first locking pin  52  of the first shield plate locking means  48  described below. 
         [0070]    As shown in  FIG. 8B , the first shield plate locking means  48  has an elastic plate-shaped member, for example, a first locking plate  51  formed of a plate spring. The first locking plate  51  has a central portion which is formed in an arc shape in the Y(−) direction, and the first locking pin  52  is provided at the central portion of an arc-shaped surface  51   a.  The first locking pin  52  may be embedded with a columnar pin or may be formed in a convex shape by drawing. Both ends of the first locking plate  51  in the X direction are formed in a flat plate shape, and attachment holes  51   c  are formed to which the shield plate guides  44  are attached. The first locking plate  51  is attached to the surfaces  44   a  of the shield plate guides  44  such that the first locking pin  52  and the arc-shaped surface  51   a  are opposite the shield plate  46 . An attachment method may be thermal caulking or fastening using screws. 
         [0071]    As shown in  FIGS. 6B and 8A , the main body case  31  is formed with a through hole  53  which passes therethrough to the outer surface in the vicinity of a position where the first locking pin  52  of the first locking plate  51  is arranged. In the initial state shown in  FIG. 8A , the shield plate actuation mechanism  45  structured as above can put the opening  35  of the data storage device  300  in the open state by locking the shield plate  46  which is urged in the Z(−) direction by the spring  47  and applied with a spring force, to the first locking pin  52  of the first locking plate  51 . 
         [0072]    As shown in  FIG. 8C , the second shield plate locking means  49  is provided near the connector  91  of the relay portion  95  in the printer main body section  180 . The second shield plate locking means  49  includes a second locking pin  54 . The position of the second locking pin  54  corresponds to the position of the through hole  53  provided in the main body case  31  when the printer main body section  180  and the data storage device  300  are connected to each other by the internal connection terminal  43  and the connector  91 . 
         [0073]    Next, the operation of the shield plate actuation mechanism will be described with reference to  FIGS. 8A to 10 . As described above,  FIG. 8A  shows the initial state, that is, the state before the data storage device  300  is connected to the printer main body section  180 .  FIG. 9A  shows the state where the data storage device  300  is connected to the printer main body section  180 .  FIG. 9B  shows the state after the data storage device  300  is separated from the printer main body section  180 . The description of  FIG. 8A  will be omitted. 
         [0074]    As shown in  FIG. 10 , the data storage device  300  is inserted from an insertion port  205   a  formed at the rear of the lower case  205  of the exterior case  200 , and the single internal connection terminal  43  is connected to the single connector  91  arranged in the relay portion  95  of the printer main body section  180 . At this time, as shown in  FIG. 9A , the second locking pin  54  is inserted into the through hole  53  of the main body case  31 . The inserted second locking pin  54  presses the periphery of the central portion of the surface  51   a  of the first looking plate  51  of the first shield plate locking means  48  in the inward direction, that is, in the Y(+) direction. The first locking plate  51  has the central portion which is formed of a plate spring curved in an arc shape in the Y(−) direction. Thus, if the first locking plate  51  is pressed at a predetermined distance, the arc portion which is curved in the Y(−)direction is curved in the Y(+) direction. 
         [0075]    For this reason, the first locking pin  52  of the first locking plate  51  moves in the Y(+) direction. The shield plate  46  which is locked to the first locking pin  52  is unlocked, such that the shield plate  46  is urged by the spring  47  and moves in the Z(−) direction. Meanwhile, the movement of the shield plate  46  which has tried to move is inhibited by the second locking pin  54  serving as the second shield plate locking means  49  inserted in the through hole  53  in the movement area and locked to the second locking pin  54 . For this reason, while the data storage device  300  is initially connected to the printer main body section  180  and functions as the thermal printer  100 , the shield plate  46  is locked to the second locking pin  54 , such that the opening  35  is kept in the open state. 
         [0076]    As shown in  FIG. 9B , if the data storage device  300  is disconnected from the printer main body section  180 , the second locking pin  54  provided in the printer main body section  180  is removed from the through hole  53  of the main body case  31 . The shield plate  46  which is urged in the Z(−) direction by the spring  47  and locked to the second locking pin  54  is unlocked and moves in the Z(−) direction. The shield plate  46  moves up to the opening  35  of the main body case  31  and shields the opening  35 . For this reason, the connection portion of the internal connection terminal  43  arranged behind the opening  35  of the main body case  31  is shielded by the shield plate  46 , such that connection from the outside is impossible. 
         [0077]    Hereinafter, the advantages of the embodiment will be described. 
         [0078]    The law (fiscal law) demands that the data storage device  300  is structured so as to be not easily disconnected from the printer main body section  180 , and when the data storage device  300  is disconnected without permission, the history of the disconnection is retained, unauthorized access to the fiscal memory  81  is impossible, and reconnection is impossible after data falsification. 
         [0079]    The above-described data storage device  300  is structured such that the internal connection terminal  43  which is connected to the connector  91  of the printer main body section  180  is arranged. inside the main body case  31 , and the connection portion is exposed from the opening  35  of the main body case. The data storage device  300  has the shield plate  46  which shields the opening. The shield plate  46  can be actuated by the above-described shield plate actuation mechanism  45 . 
         [0080]    Specifically, in the initial state, the shield plate  46  is locked to the first locking pin  52  of the first shield plate locking means  48 , and the opening  35  is in the open state. When the data storage device  300  is connected to the printer main body section  180 , the shield plate  46  is unlocked from the first locking pin  52  of the first shield plate locking means  48  and locked to the second locking pin  54  of the second shield plate locking means  49  provided in the printer main body section  180 . When the data storage device  300  is separated from the printer main body section  180 , the shield plate  46  is unlocked from the second locking pin  54  of the second shield plate locking means  49  provided in the relay portion  95  of the printer main body section  180  and shields the opening  35  of the data storage device  300 . 
         [0081]    That is, the internal connection terminal  43  serving as the connection terminal of the data storage device  300  can be hidden. For this reason, it is possible to prevent unauthorized access from the internal connection terminal  43  of the data storage device  300 . Disconnection of the data storage device  300  can be obviously known, and then reconnection is impossible. As a result, it is possible to prevent the data storage device  300  from being easily disconnected from the printer main body section  180 . Therefore, the risk of unauthorized access or data falsification is reduced, providing the high-reliability data storage device  300 . 
         [0082]    Although the embodiment of the invention has been described, various modifications may be made from the embodiment without departing from the spirit and scope of the invention. For example, the modifications other than the embodiment arc as follows. 
         [0083]    (Modification 1) Although in the above-described embodiment, a case has been described where the shield plate  46  is guided by the shield plate guides  44  and slides, the invention is not limited thereto. The rotation center constituted by a hole and a pin may be provided at a part of the shield plate  46 . The rotation direction may be the direction parallel to the inner surface  31   c  of the main body case  31 , and the shield plate  46  may slide. The rotation direction may be the direction perpendicular to the inner surface  31   c  of the main body case  31 , and the shield plate  46  may operate to open/close the opening  35 . The spring serving as urging means is not limited to a compressed coil spring, a tension coil spring, or a torsion coil spring. Any spring may be used insofar as a predetermined urging force can be given. 
         [0084]    (Modification 2) Although in the above-described embodiment, a case has been described where the first locking plate Si of the first shield plate locking means  48  is the plate spring which is formed in an arc shape with both ends fixed, the invention is not limited thereto. The first locking plate  51  may have a function of being deformed in the direction opposite to the locking direction of the first locking pin  52  with the progress of the second locking pin  54 , and may be, for example, a cantilevered plate member or a spring, such as a torsion spring. The first shield plate locking means  48  and the second shield plate locking means  49  may be provided with a locking member or a relay member halfway due to the spatial restrictions of the installation place.