Abstract:
A head protection device in a data recording circuit is disclosed in which write-current of a given level that corresponds to a high or low level of coercive force of the magnetic recording portion of a recording medium is provided as an output and supplied to a magnetic head for data recording and reproduction. The data recording circuit comprises an alternate write-current supply portion for alternately providing, by a suitable current switching means, a low write-current corresponding to a low coercivity magnetic head and a high write-current corresponding to a high coercivity magnetic head, a common output portion for providing data to be recorded using a low current or a high current from the alternate write-current supply portion. The low coercivity magnetic head and the high coercivity magnetic head can be at least electrically switched. A current protection portion for a current switching means is provided so as to prevent generation of high write-current at the alternate write-current supply portion.

Description:
BACKGROUND OF THE INVENTION 
     a) Field of the Invention 
     The present invention relates to a head protection device in a data recording circuit in which write-current is supplied to a magnetic head, which acts on a data storage section of a data storage medium, and a card reader having the head protection device. 
     b) Description of the Related Art 
     Generally, magnetic data on magnetic strips or the like] that represent a magnetic recording section formed on a data storage media (e.g. magnetic card), are recorded and reproduced utilizing a magnetic head. Lately, two types of coercivity levels, a high end and a low end, have been standardized for use in a magnetic recording section. For example, in the area of magnetic cards, in addition to conventional low-coercivity cards (300 Oe, 650 Oe) under JIS (Japanese Industrial Standards) or ISO (International Standardization Organization), high coercivity cards (2500-4200 Oe) have been newly standardized. Herein, the use of a high coercivity magnetic recording section is advantageous from the standpoint of protection of magnetic data recorded in a magnetic recording section. However, it has the drawback that a device equipped with a magnetic head that reads or writes a high coercivity magnetic recording section (hereinafter referred to as “a high coercivity magnetic head”) must be readily available. In addition, the magnetic head that reads or writes low coercivity (hereinafter referred to as “a low coercivity magnetic head”) requires a circuit different from that used for a high coercivity magnetic head, therefore, separate devices, one for low coercivity and the other for high coercivity, must be prepared for alternate use. 
     To solve the problem presented in prior art, the inventor of the present invention developed a data recording circuit, where write-current is supplied to a magnetic head that alternately generates write-current that corresponds to each of the low and the high coercivity magnetic heads. Note that the data recording circuit is not known to the public at the time of filing this patent application. 
     More specifically the data recording circuit, that can accommodate both a low coercivity magnetic head and a high coercivity magnetic head operates in the following manner.  FIG. 3 , for example, illustrates that alternate write-current supply portion  2  is provided on the output side of CPU  1 , where two types of write-currents are alternately output. Either a low write-current (Lo-Co Current) or a high write-current (Hi-Co current) from low voltage source  2   a  and high voltage source  2   b  respectively, flows into common output portion  3 . Common output portion  3  is provided by CPU  11  with recording data signal S 1  and recording gate signal S 2  such that a low coercivity magnetic head  4  or high coercivity magnetic head  5  obtain each S 1  and S 2  by means of the above-mentioned Lo-Co current or Hi-Co current. 
     Herein, a low coercivity magnetic head  4  and a high coercivity magnetic head  5  can be alternately attached to or removed from common output portion  3 . Both the low coercivity magnetic head and the high coercivity magnetic head can be alternately used in a single device, thereby reducing capital cost and providing an easy-to-use feature. 
     Nonetheless, the concept of one device having both a low coercivity magnetic head and a high coercivity magnetic head in an interchangeable manner has the drawback in that erroneous recognition occurs of whether it is a high coercivity magnetic head or a low coercivity magnetic head that is connected thereto. Particularly, when a low coercivity magnetic head is connected to the device, the circuit can be erroneously set up for Hi-Co current for a high coercivity magnetic head. Even if the setting is correct, there is concern about errors on the circuit side or the CPU that they might allow an excessive amount of current to flow into the low coercivity magnetic head, damaging the head or circuit. 
     OBJECT AND SUMMARY OF THE INVENTION 
     The present invention, as its primary object, provides a head protection device of a simple configuration that can prevent heads or circuitry from damage and a card reader having the head protection device. 
     To accomplish the above-mentioned objective, a head protection device is provided wherein the data recording circuit comprises: an alternate write-current supply portion for alternately providing, by a suitable current switching means, a Lo-Co current corresponding to a low coercivity magnetic head and a Hi-Co current corresponding to a high coercivity magnetic head; a common output portion for outputting data to be recorded using the Lo-Co current or the Hi-Co current from the alternate write-current supply portion, wherein the low coercivity magnetic head and the high coercivity magnetic head can be at least electrically switched, and a current protection portion for current switching means is provided so as to prevent generation of Hi-Co current at the alternate write-current supply portion. 
     In other words, according to the head protection device having the above-mentioned configuration, a write-current path for supplying write-current to either the low coercivity magnetic head or the high coercivity magnetic head, is configured in one data recording circuit. As a result, a low coercivity magnetic head or a high coercivity magnetic head can be alternately selected for use in a single device. In addition, the current protection portion provided in the data-recording path prevents a low coercivity magnetic head from excessive flow of write-current. 
     A card reader having the head protection device is also provided wherein the data recording circuit comprises: a suitable write-current supply portion for alternately providing, by an arbitrary current switching means, a Lo-Co current corresponding to a low coercivity magnetic head and a Hi-Co current corresponding to a high coercivity magnetic head; and a common output portion for outputting data to be recorded using a low current or a Hi-Co current from the alternate write-current supply portion, wherein the low coercivity magnetic head and the high coercivity magnetic head can be at least electrically switched, and a current protection portion for the current switching means is provided so as to prevent generation of Hi-Co current at the alternate write-current supply portion. 
     In other words, according to the head protection device having a head protection device having the above-mentioned configuration, a write-current path for supplying write-current to the low coercivity magnetic head and the high coercivity magnetic head, is configured in one data recording circuit. As a result, a low coercivity magnetic head and a high coercivity magnetic head can be alternately selected for use in a single device. In addition, the current protection portion provided in the data-recording path prevents a low coercivity magnetic head from excessive flow of write-current. 
     In the head protection device or a card reader having the head protection device, furthermore, a high coercivity magnetic head can mechanically be attached to or removed from the common output portion via the connection board having a given resistivity, and at the same time, a board connection detection means is provided both on the current protection portion and the connection board so as to sense whether the connection board is connected to the current protection portion side. 
     According to the head protection device and a card reader having the head protection device, only by mechanically attaching to or removing from the high coercivity magnetic head, one can let the data recording side recognize whether the high coercivity head is attached or connected to the common output portion via a connection board. This is a simple configuration but provides an easy-to-handle feature. 
     Moreover, in the head protection device or a card reader having the head protection device, the current switching means of the current protection portion switches, upon reception of a confirmation signal from the connection board side, such that a Hi-Co current is generated in the alternate write-current supply portion. 
     According to the head protection device and a card reader having the head protection device, the current switching means in the current protection portion is automatically (electrically) actuated. 
     The head protection device or a card reader having the head protection device, wherein the switching means is configured in an electrical circuit or control software, therefore, it can be configured in many different ways. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a block diagram showing the circuit of the head protection device of a card reader according to Embodiment 1 of the present invention; 
         FIG. 2  is a block diagram of a circuit of an alternate embodiment of the present invention; and 
         FIG. 3  is a block diagram showing a circuit of the head protection device adopted in a general card reader. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention are described in detail herein with reference to the drawings. 
     First,  FIG. 1  shows an embodiment of the head protection device in a card reader, which is one of the back-end devices in the automated teller machine (not illustrated), the front-end device. Each of the operations performed in the card reader as a back-end device, is controlled based on commands coming from the body of the automated teller machine, the front-end device, so as to interrelate operations between the two systems. 
     In other words, a recording command signal is sent as required from the body of the automated teller machine, the upper device, to CPU  11  provided in the data recording circuit of the card reader. Based on the recording command signal, an output command signal (HCW signal) for commanding output of write-current that corresponds to the magnetic strip (magnetic recording portion) of a magnetic card currently in use is sent from CPU  11  to alternate write-current supply portion  12 . The output command signal (HCW signal) commands comprises a “Lo-signal” for commanding output of a Lo-Co current corresponding to a low coercivity magnetic strip and a “Hi-signal” for commanding output of a Hi-Co current for commanding output of the Hi-Co current corresponding to a high coersivity magnetic strip. 
     In current alternate supply portion  12  is provided low voltage (+12V) power supply  12   a  and high voltage (+24V), wherein the supply current path is switched in response to an output command from CPU  11  to either the low voltage source  12   a  side or the high voltage source  12   b  side such that either the Lo-Co current or the Hi-Co current is selectively supplied to common output portion  13  in the manner described below. 
     More specifically, if the output command signal (HCW signal) sent from CPU  11  to alternate write-current supply portion  12  is the “Lo-signal”, the base side of the transistor Q 2 , a current switching means, becomes the Lo level (mode) and puts the transistor Q 2  in the “OFF” state. As a result, the base side of transistor Q 3 , connected to the collector side of transistor Q 2  to provide current switching means, enters the Hi level mode, putting transistor Q 3  in the “OFF” state. As a result of this, the supply current path connected to the collector side of transistor Q 3  is switched to the side where low voltage source  12   a  is located. The above-mentioned Lo-Co current is thus supplied from low voltage source  12   a  to common output portion  13 . 
     In contrast, the output command signal (HCW signal) coming from CPU  11  to alternate write-current supply portion  12  puts the base side of transistor Q 2  in the Hi level (mode), resulting in putting transistor Q 2  in the “ON” state. In turn, the base side of transistor Q 3  is switched to the Lo level (mode), turning transistor Q 3  on. The current path is thus switched to the high voltage source  12   b  side wherein the high voltage source  12   b  is connected to the emitter side of transistor Q 3 . The Hi-Co current is thus supplied from high voltage source  12   b  to common output portion  13 . 
     Write circuit  13   a  is provided in common output portion  13 , and recording data signal S 1  and recording gate signal S 2  from CPU  11  are input into write circuit  13   a . S 1  or S 2  are supplied to low coercivity magnetic head  14  and high coercivity magnetic head  15  utilizing a Lo-Co current or Hi-Co current, whichever is selected, that is further supplied to write circuit  13   a.    
     Herein, low coersivity magnetic head  14  is configured such that the a low coercivity magnetic head can be electrically turned “ON” or “OFF” by directly attaching to or removing from a pair of output connector terminals  13   b  in common output portion  13 ; the high coercivity magnetic head  15  is electrically turned “ON” or “OFF” by attaching to or removing from output connector terminal  13   b  via connection board  15   a.    
     Now, when low coercivity magnetic head  14  is attached to common output portion  13 , output from write circuit  13   a  is supplied thereto via resistor R 5 ; when high coercivity magnetic head  15  is attached to common output  13 , closure of switch SW 1 , arranged in parallel with resister R, supplies output from write circuit  13   a  along the switch SW 1  side without passing resister R 5 . 
     Moreover, a pair of input connector terminals  15   b  to be connected to a pair of output connectors  13   b  in common output portion  13 , is provided on connection board  15   a , where low coercivity magnetic head  14  or high coercivity magnetic head  15  is alternately connected as required. 
     Also, low coercivity magnetic head  14  and its current protection portion  16 , for protecting the circuit that contact low coercivity magnetic head  14 , are attached to alternate write-current supply portion  12 . In other words, current protection portion  16  is designed such that output from constant voltage (+5V) source  16   a  through resistor R 4  puts the base side of transistor Q 1  in the Hi level mode, thereby maintaining transistor Q 1  in the “ON” state. The collector side of transistor Q 1 , being maintained in the “ON” state, is connected to the base side of transistor Q 2 , which is the current switching means for alternate write-current supply portion  12 , thereby maintaining the base side of transistor Q 2  in the Low level mode all the time, maintaining transistor Q 2  in the “OFF” state. 
     When transistor Q 2  is turned off, a Lo-Co current is output from common output portion  13 , as described above. Therefore, even if there is a concern that Hi-Co current is output due to erroneous operation of the circuit or for some other reasons, Hi-Co current will not be outputted from common output portion  13  as long as low coercivity magnetic head  14  is attached to common output portion  13 . Lo-Co current is thus outputted all the time. 
     A pair of switch-connectors  15   c , that are electrically connected to each other, is provided on connection board  15   a  of high coercivity magnetic head  15  so as to constitute board connection detection means (on one side), at the same time, a pair of connection detector connectors  16   b  is provided in current protection portion  16  corresponding to a pair of switch-connectors  15   c  so as to constitute board connection means on the other side. One side (upward direction in  FIG. 1 ) is connected to the constant voltage source  16   a  side while the other (downward direction in  FIG. 1 ) connectors  16   b  are grounded. 
     Therefore, when connection board  15   a  of high coercivity magnetic head  15  is connected to common output portion  13 , switch connectors  15   c  on the connection board  15   a  side is connected to connection detection connector  16   b  on the current protection portion  16  side. By this, the current level drops to a Lo-level (mode) on the base side of transistor Q 1 , when connection of high coercivity magnetic head  15  is detected. As connection of high coercivity magnetic head  15  is detected, transistor Q 1  is turned off; the base side of transistor Q 2 , constituting the current switch means of alternate write-current supply portion  12  and being connected to the collector side of transistor Q 1 , is switched to the Hi-level (mode), turning on transistor Q 2 . As a result, Hi-Co current is output from common output portion  13  as described above. 
     Usually, the HCDCT signal (a high coercivity magnetic head detection signal) of Lo-level (mode) is detected when high coercivity magnetic head  15  is connected to common output portion  13 . In this embodiment, the HCDCT signal is also inputted into the above-mentioned CPU  11 . The software controls operation in such a way that Hi-Co current is outputted only when CPU  11  receives the HCDCT signal of Lo-level (mode). As long as high coercivity magnetic head  15  is not connected to common output portion  13 , the HCDCT signal is not received, therefore CPU  11  does not let Hi-Co current flow. 
     According to the head protection device in a card reader of this embodiment having the configuration described above, a write-current path, that supplies different levels of write-current to the low coercivity magnetic head  14  and high coercivity magnetic head  15 , is configured in a single data-recording path. This makes it possible to alternately use low coercivity magnetic head  14  and high coercivity magnetic head  15  in a single device. 
     In addition, taking advantage of current protection portion  16  attached to alternate write-current supply portion  12  of the data recording circuit, excessive write-current does not flow into low coercivity magnetic head  14 , and low coercivity magnetic head  14  and its circuitry are protected from exposure to excessive current. 
     Moreover, according to this embodiment, connection of the high coercivity magnetic head  15 , instead of low coercivity magnetic head  14 , allows output of Hi-Co current. Only mechanical attachment or removal can switch the data-recording path to serve a high coercivity magnetic head to common output portion  13 . This is a simple configuration but can provide an easy-to-operate feature. 
     Also, in the above embodiments, current switching means in alternate write-current supply portion  12  is configured on hardware, and Hi-Co current output is controlled by software. This dual protection provides excellent reliability. 
     The inventor specifically described embodiments of the present invention above, however, the present invention is not limited to the above embodiments. The present invention may be modified in many different ways as long as the spirit of the invention is maintained. 
     For example, instead of transistor Q 1  and R 1 , constituting current switching means of alternate write-current supply portion  12   a , modified circuit configuration such as a combination of inverter IC  21  and AND gate IC  22  may be employed. 
     Further, the present invention is applied to a card reader in each embodiment described above, however, the present invention may be applied to other devices of various kinds in a similar manner. 
     As described above, in one form of the invention, the head protection device of the present invention and the card reader having the head protection device have an alternate write-current supply portion which selectively switches a high or low write-current to generate write-current for the low coercivity magnetic head or the high coercivity magnetic head. This configuration makes it possible for one device to alternately accommodate both a low coercivity magnetic head and a high coercivity magnetic head. In addition, the current protection portion in the data recording circuit prevents a low coercivity magnetic head from excessive write-current. An easy-to-use feature can be thus obtained cost effectively, and the simple configuration prevents heads or their circuitry from damage, thereby providing excellent usage and reliability. 
     The head protection device or a card reader having the head protection device has a magnetic head for high coercivity that can mechanically be attached to or removed from the common output portion via a connection board having a given resistivity, and at the same time, a board connection detection means is provided on both the current protection portion and the connection board so as to sense whether the connection board is connected on the current protection portion side. Only by mechanically attaching to or removing the high coercivity magnetic head, one can let the data recording side recognize whether the high coercivity head is attached or connected to the common output portion via a connection board. This is a simple configuration but provides an easy-to-handle feature. 
     Moreover, in a further aspect of the invention, in the head protection device or a card reader having the head protection device, the current switching means of current protection portion switches, upon reception of a confirmation signal from the connection board side, such that a Hi-Co current is generated in the alternate write-current supply portion. The current switching means in the current protection portion is thus actuated automatically (electrically), and the above-mentioned effects can be further enhanced. 
     The head protection device or a card reader having the head protection device, in yet another form of the invention, the switching means is configured in an electrical circuit or control software, the switching means can be constituted in many different ways. With this additional feature, the present invention can be simple and even more cost effective. 
     While the foregoing description and drawings represent the present invention, it will be obvious to those skilled in the art that various changes may be made therein without departing from the true spirit and scope of the present invention.