JP2007233600A - Magnetic ink character reader and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic ink character reader for achieving relative low costs. <P>SOLUTION: This magnetic ink character reader is provided with a magnetic head for outputting a signal corresponding to the change of a magnetic flux due to magnetic ink characters, and configured to recognize a character string recorded in a recording medium by using one or more magnetic ink characters based on a signal to be output from the magnetic head. A peak interval data acquisition part 30 acquires peak interval data showing the peak interval of a signal to be output from the magnetic head. A reference peak interval data storage part 31 stores reference peak interval data by associating the reference peak interval data with each magnetic ink character. A comparison part 32 compares the peak interval data acquired by the peak interval data acquisition part 30 with the reference peak interval data stored in the reference peak interval data storage part 31. A recognition part 33 recognizes the character string recorded in the recording medium based on a comparison result from the comparison part 32. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic ink character reading device and a control method thereof.

  A magnetic head that outputs a signal corresponding to a change in magnetic flux caused by magnetic ink characters (MICR characters: Magnetic Ink Character Recognition characters), and a character string recorded on a recording medium using one or a plurality of magnetic ink characters; 2. Description of the Related Art A magnetic ink character reader that recognizes a signal based on a signal output from a magnetic head is known. Conventionally, in a magnetic ink character reading apparatus, A / D conversion is performed on a signal output from a magnetic head at a predetermined sampling frequency, and digital data (data indicating a waveform of a signal output from the magnetic head) obtained by A / D conversion is obtained. ) Is used to recognize magnetic ink characters (character strings) recorded on a recording medium using sample values (for example, peak values) of feature points.

  In the magnetic ink character reading apparatus as described above, an A / D converter for A / D converting a signal output from the magnetic head is required. Since the A / D converter is relatively expensive, it has been difficult to realize a magnetic ink character reader at a relatively low cost.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetic ink character reading device and a control method thereof that can realize the magnetic ink character reading device at a relatively low cost.

  In order to solve the above-described problems, a magnetic ink character reading device according to the present invention includes a magnetic head that outputs a signal corresponding to a change in magnetic flux caused by a magnetic ink character, and a recording medium using one or a plurality of magnetic ink characters. In a magnetic ink character reader that recognizes a character string recorded on the basis of a signal output from the magnetic head, peak interval data for acquiring peak interval data indicating a peak interval of the signal output from the magnetic head An acquisition means, a reference peak interval data storage means for storing reference peak interval data in association with each magnetic ink character, a peak interval data acquired by the peak interval data acquisition means, and a reference peak interval data storage means Comparison means for comparing the stored reference peak interval data, and based on the comparison result by the comparison means Characterized in that it comprises a recognition means for recognizing a character string recorded in the recording medium.

  The method for controlling a magnetic ink character reading device according to the present invention includes a magnetic head that outputs a signal corresponding to a change in magnetic flux caused by a magnetic ink character, and is recorded on a recording medium using one or a plurality of magnetic ink characters. In a method for controlling a magnetic ink character reader that recognizes a character string based on a signal output from the magnetic head, a peak for obtaining peak interval data indicating a peak interval of a signal output from the magnetic head An interval data acquisition step, reference peak interval data stored in reference peak interval data storage means for storing reference peak interval data in association with each magnetic ink character, and peaks acquired by the peak interval data acquisition means Based on the comparison step for comparing the interval data and the comparison result of the comparison step, Characterized in that it comprises a recognition step for recognizing a character string recorded in medium.

  The present invention includes a magnetic head that outputs a signal corresponding to a change in magnetic flux caused by a magnetic ink character, and a signal that is output from the magnetic head to a character string recorded on a recording medium using one or more magnetic ink characters. The present invention relates to a magnetic ink character reading device that is recognized based on the above. In the present invention, peak interval data indicating each peak interval of the signal output from the magnetic head is acquired. In the present invention, reference peak interval data is stored in association with each magnetic ink character. Then, the reference peak interval data and the peak interval data of the signal output from the magnetic head are compared, and the character string recorded on the recording medium is recognized based on the comparison result. According to the present invention, a magnetic ink character reading device can be realized at a relatively low cost.

  In the aspect of the invention, the recognizing unit includes a determining unit that determines whether a peak interval of a signal output from the magnetic head is equal to or larger than a predetermined interval, and based on a determination result by the determining unit. Then, it may be recognized whether or not a blank character is included in the character string recorded on the recording medium.

  According to another aspect of the present invention, there is provided means for outputting a signal based on a signal output from the magnetic head, and when a positive polarity signal is input from the magnetic head, the first voltage level A signal is output until a negative polarity signal is input from the magnetic head, and when a negative polarity signal is input from the magnetic head, the second voltage level is different from the first voltage level. A signal conversion unit that outputs a signal until a positive polarity signal is input from the magnetic head, and the peak interval data acquisition unit includes data indicating each pulse width of the signal output by the signal conversion unit. You may make it acquire as peak space | interval data.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing an overall configuration of a magnetic ink character reading apparatus according to an embodiment of the present invention. As shown in the figure, a magnetic ink character reading device 10 according to the present embodiment includes a control unit 11, a storage unit 12, an interface (I / F) 13, a magnetic ink character reading unit 14, and a printing unit. 15.

  The control unit 11 operates according to a program stored in the storage unit 12 and controls the magnetic ink character reading device 10 as a whole. The storage unit 12 includes a computer-readable information storage medium such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage unit 12 also operates as a work memory that stores various data for executing various processes.

  The interface 13 is for communication connection with a host computer (not shown) so as to exchange data. The interface 13 transmits various data to the host computer in accordance with instructions from the control unit 11. For example, various status information of the magnetic ink character reading device 10 and reading results of magnetic ink characters printed (recorded) on paper (recording medium) are transmitted to the host computer via the interface 13. The interface 13 receives various data from the host computer and supplies the data to the control unit 11. For example, image print data generated by various application programs in the host computer is supplied to the control unit 11 via the interface 13.

  The magnetic ink character reading unit 14 is for reading magnetic ink characters printed on paper. The control unit 11 recognizes the magnetic ink characters printed on the paper based on the data supplied from the magnetic ink character reading unit 14. That is, a character string printed using magnetic ink characters on paper is recognized. The character string recognized by the control unit 11 is transmitted to the host computer via the interface 13 and used for various processes. The operation of the magnetic ink character reading unit 14 will be described later.

  The printing unit 15 is for printing an image on a sheet. The control unit 11 interprets print data supplied from the host computer via the interface 13 and converts it into raster image data. The control unit 11 supplies the raster image data to the printing unit 15 for printing.

  As described above, the magnetic ink character reader 10 has a function of reading a character string recorded on a recording medium using magnetic ink characters and a function of printing an image on the recording medium. The magnetic ink character reader 10 is used in the following manner, for example, in check settlement at a retail store or the like. That is, a person in charge at a retail store or the like receives a check from the product purchaser, and prints store identification information, a purchase price, and the like on the check. For this printing, the printing unit 15 of the magnetic ink character reading device 10 is used. Next, the merchandise purchaser confirms the store identification information printed on the check, the purchase amount, etc., and signs the check. Then, the person in charge at the store receives the signed check, and causes the magnetic ink character reading device 10 to read the account number or the like printed with magnetic ink characters on the surface of the check. The read account number or the like is transmitted to the host computer via the interface 13 and its validity is confirmed. When the validity of the account number or the like is confirmed, the fact is printed on the check by the printing unit 15, and the check settlement is completed.

  Here, the magnetic ink character reading unit 14 will be described in more detail. FIG. 2 is a schematic diagram showing the mechanism of the magnetic ink character reading unit 14. As shown in FIGS. 1 and 2, the magnetic ink character reading unit 14 includes a paper sensor 16 (paper sensors 16 a and 16 b), a conveyance roller 17, a conveyance motor 18, a conveyance motor drive control unit 19, and a magnet 20. And a magnetic head 21, a magnetic detection signal processing circuit unit 22, and a timer unit 23.

  The paper sensor 16 a detects whether or not the paper 24 is inserted into a predetermined insertion port of the magnetic ink character reading device 10. The transport roller 17 transports the paper 24 inserted into the insertion port at a constant speed. When the paper 24 is transported by the transport roller 17, relative movement between the magnetic head 21 and the paper 24 is realized. The carry motor 18 includes a step motor for rotating the carry roller 17 at a constant speed. The carry motor drive control unit 19 controls the drive of the carry motor 18. When the paper sensor 16a detects that the paper 24 has been inserted into the insertion slot, the control unit 11 causes the carry motor drive control unit 19 to drive the carry motor 18. When the carry motor 18 is driven, the carry roller 17 is rotated in the A direction (clockwise direction) shown in FIG. 2, and the paper 24 is carried in the B direction shown in FIG. At this time, the sheet 24 is sandwiched between the magnetic head 21 and the transport roller 17.

  The area on the surface 24 a of the paper 24 where the magnetic ink characters are printed is magnetized by the magnet 20. The magnetic head 21 is an element that detects a change in magnetic flux. The magnetic head 21 outputs a signal (magnetic detection signal) corresponding to a change in magnetic flux due to magnetic ink characters printed on the surface 24 a of the paper 24. The magnetic detection signal output from the magnetic head 21 is input to the magnetic detection signal processing circuit unit 22.

  Here, the magnetic detection signal output from the magnetic head 21 will be described. In the present embodiment, magnetic ink characters defined in JIS X9002 are to be read. JIS X9002 defines 14 types of magnetic ink characters (strokes 0 to 13). Strokes 0-9 correspond to numbers 0-9, respectively. Each of the strokes 10 to 13 corresponds to a predetermined symbol. FIG. 3A shows an example of magnetic ink characters defined in JIS X9002. Here, stroke 0 and stroke 8 are shown. As shown in the figure, each magnetic ink character is defined to fit within a rectangle in which nine squares each having a side length of 0.33 mm are arranged vertically and seven horizontally. In JIS X9002, the pitch of each magnetic ink character is defined as 3.175 mm.

  FIG. 3B shows a magnetic detection signal output from the magnetic head 21 when the magnetic ink characters shown in FIG. As shown in FIG. 4B, at least a part of the detection target area of the magnetic head 21 changes from an area where the magnetic ink characters are not printed on the paper 24 to an area where the magnetic ink characters are printed (A , C, E, F, H), that is, at the timing when the magnetic flux increases, a positive pulse is output from the magnetic head 21. Further, the timing (B, D, G, I, J) when at least a part of the detection target area of the magnetic head 21 changes from the area where the magnetic ink characters are printed on the paper 24 to the area where the magnetic ink characters are not printed. ), That is, at the timing when the magnetic flux decreases, a negative pulse is output from the magnetic head 21.

  The magnetic detection signal processing circuit unit 22 converts the magnetic detection signal input from the magnetic head 21 into a digital signal (digital data). More specifically, when a positive polarity magnetic detection signal is input from the magnetic head 21, the magnetic detection signal processing circuit unit 22 sets the voltage level of the output signal to H (High) level, and the negative polarity from the magnetic head 21. When a magnetic detection signal is input, the voltage level of the output signal is reset to L (Low) level to convert the magnetic detection signal input from the magnetic head 21 into a digital signal.

  FIG. 4 is a functional block diagram of the magnetic detection signal processing circuit unit 22. FIG. 5 is a circuit diagram showing an example of the circuit of the magnetic detection signal processing circuit unit 22. As shown in these drawings, the magnetic detection signal processing circuit unit 22 includes a differential amplifier 22a, a differentiation circuit 22b, a low-pass filter 22c, a differentiation circuit 22d, an inversion circuit 22e, and a comparator 22f. Composed.

  The magnetic detection signal input from the magnetic head 21 is amplified by being DC biased (DC level shift) by the differential amplifier 22a. In the present embodiment, the magnetic detection signal input from the magnetic head 21 is DC biased by 2.5 V by the differential amplifier 22a. FIG. 3C shows the magnetic detection signal amplified by the differential amplifier 22a.

  The peak of the magnetic detection signal amplified by the differential amplifier 22a is emphasized by the differentiation circuit 22b, and the noise component is removed by the low-pass filter 22c. The magnetic detection signal from which the noise component has been removed by the low-pass filter 22c is input to the comparator 22f via the differentiation circuit 22d and the inverting circuit 22e. The comparator 22f is a comparator with hysteresis. That is, when a pulse of a reference voltage (2.5 V in this embodiment) or more is input, the comparator 22f continues to output an H level signal until a pulse less than the reference voltage is input. Further, when a pulse less than the reference voltage is input, the comparator 22f continues to output an L level signal until a pulse equal to or higher than the reference voltage (2.5 V in the present embodiment) is input. The digital signal output from the magnetic detection signal processing circuit unit 22 is input to the timer unit 23.

  Here, the digital signal output from the magnetic detection signal processing circuit unit 22 will be described.

  FIG. 3D shows a digital signal output from the magnetic detection signal processing circuit unit 22 when the magnetic ink characters shown in FIG. In other words, a digital signal output from the magnetic detection signal processing circuit unit 22 when the magnetic detection signal shown in FIG. As shown in FIG. 4D, at the timing when a positive pulse is input from the magnetic head 21, output of an H level signal is started (A, C, E, H), and the negative polarity is output from the magnetic head 21. Output of an L level signal is started at the timing when a pulse is input (B, D, G, I). Further, as shown in FIG. 4D, the width of each pulse of the digital signal output from the magnetic detection signal processing circuit unit 22 is the positive peak and negative polarity of the magnetic detection signal output from the magnetic head 21. It corresponds to the interval with the peak. More specifically, the width of the H level pulse corresponds to the interval from the positive polarity peak of the magnetic detection signal output from the magnetic head 21 to the next negative polarity peak. The width of the L-level pulse corresponds to the interval from the negative polarity peak of the magnetic detection signal output from the magnetic head 21 to the next positive polarity peak.

  When each magnetic ink character defined by JIS X9002 is read, for example, a digital signal as shown in FIG. 6 is output from the magnetic detection signal processing circuit unit 22.

  The timer unit 23 acquires the polarity and width of each pulse of the digital signal input from the magnetic detection signal processing circuit unit 22. Each time the timer unit 23 acquires the polarity and width of one pulse, it supplies pulse width data indicating the acquisition result to the control unit 11. The control unit 11 causes the storage unit 12 to sequentially store the pulse width data sequentially supplied from the timer unit 23. As a result, the storage unit 12 stores a pulse width data string indicating the polarity and width of each pulse of the digital signal input from the magnetic detection signal processing circuit unit 22.

  FIG. 7 is a diagram showing an example of a pulse width data string. The pulse width data sequence shown in the figure shows an example in which the magnetic ink characters shown in FIG. 3A are read. In the pulse width data sequence shown in FIG. 7, as shown in FIG. 3D, the time required for the relative movement of 0.33 mm between the magnetic head 21 and the paper 24 is T. In the pulse width data sequence shown in FIG. 7, the width of the H level pulse is held as a positive value, and the width of the L level pulse is held as a negative value. In the pulse width data string shown in FIG. 7, the underlined pulse width data is a pulse (L) output from the magnetic detection signal processing circuit unit 22 due to a margin between the stroke 0 and the stroke 8. Level pulse) data. Here, the length of the width of such a pulse is assumed to be 2T. Actually, an L-level pulse having a relatively long pulse width is output until the detection target area of the magnetic head 21 reaches the print target area of the first magnetic ink character on the paper 24, and the magnetic head 21 An L-level pulse having a relatively long pulse width is output after the detection target area has passed the printing target area of the last magnetic ink character on the paper 24, but is omitted here.

  The operation of the magnetic ink character reading unit 14 described above is repeated until the paper 24 is no longer detected by the paper sensor 16b provided downstream of the magnetic head 21, or until the paper 24 is conveyed by a predetermined amount by the conveying roller 17. It is.

  Next, a configuration for recognizing a character string (magnetic ink character) printed on the paper 24 based on the pulse width data sequence stored in the storage unit 12 will be described.

  FIG. 8 is a diagram mainly showing functions related to the present invention among the functions realized by the magnetic ink character reading device 10. As shown in FIG. 1, the magnetic ink character reading device 10 includes a peak interval data acquisition unit 30, a reference peak interval data storage unit 31, a comparison unit 32, and a recognition unit 33.

[1. Peak interval data acquisition unit]
The peak interval data acquisition unit 30 is realized mainly by the timer unit 23. The peak interval data acquisition unit 30 acquires peak interval data indicating the peak interval of the magnetic detection signal output from the magnetic head 21. In the present embodiment, the peak interval data acquisition unit 30 acquires a pulse width data string (FIG. 7) indicating the width of each pulse of the digital signal output from the magnetic detection signal processing circuit unit 22 as peak interval data. To do.

[2. Reference peak interval data storage unit]
The reference peak interval data storage unit 31 is realized mainly by the storage unit 12 (ROM). The reference peak interval data storage unit 31 stores reference peak interval data in association with each magnetic ink character. In the case of this embodiment, a reference pulse interval data storage unit 31 stores a reference pulse width data sequence table in which each magnetic ink character is associated with a reference pulse width data sequence (reference peak interval data).

  FIG. 9 shows an example of the reference pulse width data string table. As shown in FIG. 6, the maximum number of pulses included in the digital signal corresponding to each magnetic ink character is five. Therefore, in the reference pulse width data string table shown in FIG. 9, the reference pulse width data string of each magnetic ink character is held as vector data (array data) consisting of five elements. For magnetic ink characters with the number of pulses less than 5, the reference pulse width data string is set as five-dimensional vector data by setting 0 to one or more elements.

[3. Comparison part]
The comparison unit 32 is realized mainly by the control unit 11 and the storage unit 12. The comparison unit 32 compares the peak interval data acquired by the peak interval data acquisition unit 30 with the reference peak interval data stored in the reference peak interval data string storage unit 31. This comparison is performed using a general pattern matching method. Details will be described later.

[4. Recognition unit]
The recognition unit 33 is realized mainly by the control unit 11 and the storage unit 12. The recognition unit 33 recognizes a character string (magnetic ink character) recorded on the paper 24 based on the comparison result by the comparison unit 32. The recognizing unit 33 determines whether or not the peak interval of the magnetic detection signal output from the magnetic head 21 is equal to or greater than a predetermined interval, and the character string recorded on the paper 24 is blank based on the determination result. Recognizes whether a character is included.

  Here, processing executed in the magnetic ink character reading device 10 will be described. 10 to 12 are flowcharts showing processing executed in the magnetic ink character reading device 10. By executing this process by the control unit 11, the comparison unit 32 and the recognition unit 33 are realized.

  As shown in FIG. 10, first, a character string type variable s is initialized (S101). Specifically, the character string held in the character string type variable s is initialized to an empty character string (character string of length 0). This character string type variable s is used to hold the recognition result of the character string printed on the paper 24.

  Next, the first pulse width data of the pulse width data held in the pulse width data string (FIG. 7) is the target pulse width data, and the target pulse width data Δw is read (S102). As described above, the target pulse width data Δw indicates the width of the H level pulse as a positive value and the width of the L level pulse as a negative value.

  Then, processing (S103 to S110) for cutting out the first pulse width data string for one character is executed. As shown in FIG. 6, since the first pulse of the digital signal corresponding to the magnetic ink character is always an H level pulse, the value of the pulse width data Δw of interest is a positive value for one character. This is a start condition for extracting a pulse width data string (see S103). The final state of the digital signal corresponding to the magnetic ink character is always L level, and the length of the digital signal corresponding to the magnetic ink character is the width of the magnetic ink character (0.33 mm × 7). This is a time required for relative movement between the magnetic head 21 and the paper 24 (here, this time length is described as a reference value Ta (= 7T)). For this reason, the value of the target pulse width data Δw is a negative value, and the total value of the pulse widths is equal to or greater than the reference value Ta is the extraction end condition for the pulse width data string for one character (S107). reference).

  In the process for cutting out the pulse width data string for one character, it is first determined whether or not the value of the target pulse width data Δw is a positive value (S103). In other words, it is determined whether or not the extraction start condition of the pulse width data string for one character is satisfied. When the value of the target pulse width data Δw is a positive value, the variables i and w are initialized to 0 (S104). Further, the value of each element of the array P is initialized to 0 (S105). The array P includes at least five elements and is used to hold a pulse width data string for one character.

  Next, the absolute value of the target pulse width data Δw is added to the value of the variable w (S106). Then, it is determined whether or not the value of the target pulse width data Δw is a negative value and the value of the variable w is equal to or greater than the reference value Ta (S107). That is, it is determined whether or not the extraction end condition of the pulse width data string for one character is satisfied.

  When the value of the target pulse width data Δw is a positive value, or when the value of the variable w is less than the reference value Ta, the value of the element i of the array P is updated to the value of the target pulse width data Δw ( S108). Further, the value of the variable i is incremented (S109). Further, the next pulse width data among the pulse width data held in the pulse width data string (FIG. 7) is set as the noticed pulse width data, and the noticed pulse width data Δw is read (S110). Then, the processing from S106 to S110 is executed again.

On the other hand, if it is determined in S107 that the value of the target pulse width data Δw is a negative value and the value of the variable w is greater than or equal to the reference value Ta, the pulse width data for one character is stored in the array P. The column will be retained. For example, when the pulse width data sequence shown in FIG. 7 is stored in the storage unit 12, the array P includes (P ₁ , P ₂ , P ₃ , P ₄ , P ₅ ) = (T, −5T, T, 0, 0) is held.

  In this case, by comparing this one-character pulse width data string with the reference pulse width data string (FIG. 9) of each magnetic ink character, the magnetic ink character corresponding to this one-character pulse width data string is specified. The process (S111 thru | or S118) for performing is performed.

  First, variables j, k, and rm are initialized to 0 (S111). Next, the reference pulse width data string Q of the stroke j is read from the storage unit 12 (S112). Then, the similarity r between the array P and the reference pulse width data string Q is calculated (S113). A formula for calculating the similarity r is shown in Formula (1).

  As shown in the above equation (1), the similarity r is obtained by dividing the inner product of the array P and the reference pulse width data string Q by the product of the absolute value of the array P and the absolute value of the reference pulse width data string Q. Is calculated by The similarity r is a value between −1 and 1 inclusive. The larger the value, the higher the similarity between the array P and the reference pulse width data string Q.

  Next, it is determined whether or not the value of similarity r is greater than the value of variable rm (S114). If the value of similarity r is greater than the value of variable rm, the value of variable rm is updated to the value of similarity r, and the value of variable k is updated to the value of variable j (S115).

  After the process of S115 is executed or when it is determined in S114 that the value of the similarity r is equal to or less than the value of the variable rm, it is determined whether or not the value of the variable j is 13 (S116). That is, it is determined whether or not the similarity r has been calculated for all magnetic ink characters.

  If the value of the variable j is not 13, the value of the variable j is incremented (S117), and the processes from S112 to S116 are executed again.

  On the other hand, when the value of the variable j is 13, the stroke k is specified as a magnetic ink character corresponding to the array P (a pulse width data string for one character acquired by the processing of S103 to S110). That is, the magnetic ink character having the highest similarity r between the array P and the reference pulse width data string Q is specified as the magnetic ink character corresponding to the array P. Then, a character corresponding to the stroke k is added to the end of the character string held in the character string type variable s (S118). For example, when the value of the variable k is 0, the character corresponding to the stroke 0, that is, “0” is added to the end of the character string held in the character string type variable s. For example, when the value of the variable k is 10, a character corresponding to the stroke 10, for example, “A” is added to the end of the character string held in the character string type variable s.

  After the process of S118 is executed or when it is determined in S103 that the value of the target pulse width data Δw is a negative value, is the target pulse width data Δw the pulse width data corresponding to the blank character? It is determined whether or not (S119). A time (Ta) or more required for the relative movement between the magnetic head 21 and the paper 24 for the width (0.33 mm × 7) of the magnetic ink character (here, this time length is referred to as a reference value Tb). In the case where the L level pulse is continuously output from the magnetic detection signal processing circuit unit 22, the pulse is detected until the detection target area of the magnetic head 21 reaches the print target area of the first magnetic ink character. It may be considered that a blank character is printed except for a pulse that is output in between or a pulse that is output after the detection target area of the magnetic head 21 has passed the printing target area of the last magnetic ink character. it can. Therefore, in this step, 1) the value of the target pulse width data Δw is a negative value, 2) the absolute value of the target pulse width data Δw is greater than or equal to the reference value Tb, and 3) the target pulse width data. Δw is not the first pulse width data in the pulse width data string (FIG. 7), and 4) the target pulse width data Δw is the last pulse width data in the pulse width data string (FIG. 7). It is determined whether or not the condition “No” is satisfied. If this condition is satisfied, a blank character is added to the end of the character string stored in the character string type variable s (S120).

  After the process of S120 is executed or when it is determined in S119 that the above condition is not satisfied, the pulse width data Δw of interest is the last pulse width data in the pulse width data string (FIG. 7). It is determined whether or not there is (S121). When the target pulse width data Δw is not the last pulse width data in the pulse width data string, the next pulse width data in the pulse width data string is set as the target pulse width data, and the target pulse width data Δw is It is read (S122). Then, the processes from S103 to S121 are executed again. That is, processing for cutting out the pulse width data string for the next one character is executed (S103 to S110), and thereafter processing for specifying the next magnetic ink character (S111 to S117) is executed.

  On the other hand, when it is determined in S121 that the target pulse width data Δw is the last pulse width data in the pulse width data string (FIG. 7), this processing ends. In this case, the character string type variable s holds the recognition result of the character string (magnetic ink character) printed on the paper 24. The contents of the character string type variable s are transmitted to the host computer or the like via the interface 13 and provided for each processing.

  When the reading of the character string (magnetic ink characters) printed on the paper 24 is normally completed, the paper 24 is conveyed to the printing unit 15. On the other hand, if the reading of the magnetic ink characters fails, the transport roller 17 is rotated in the reverse direction, and the paper 24 is returned to the initial position (insertion opening).

  The success or failure of reading the magnetic ink character may be determined based on the number of peaks of the magnetic detection signal output from the magnetic head 21, the type of format of the read magnetic ink character, or the like. For example, when the number of peaks of the magnetic detection signal output from the magnetic head 21 is a predetermined number or less, the paper 24 is not inserted in a normal orientation (for example, the paper 24 is inserted with the front and back sides reversed. It may be determined that the reading of the magnetic ink character has failed.

  The success or failure of reading magnetic ink characters is based on the highest similarity value, the difference between the highest similarity and the second highest similarity, etc., each time one character is read (recognized). You may make it judge. For example, when the value of the variable rm (the highest similarity) is equal to or less than a predetermined value during the process of S118, it may be determined that reading of the magnetic ink characters has failed.

  Further, when it is determined that reading of the magnetic ink characters has failed and the paper 24 is returned to the initial position (insertion slot), the reading of the magnetic ink characters may be automatically re-executed. . Such re-execution may be repeated until the reading of the magnetic ink characters is completed normally. If the number of peaks of the magnetic detection signal output from the magnetic head 21 is equal to or less than the predetermined number, the sheet 24 may not be inserted in a normal direction, and thus such re-execution is limited. (Suppression) may be performed. The presence / absence of re-execution and the number of re-executions may be set by transmitting predetermined command data from the host computer to the magnetic ink character reading device 10.

  As described above, in the magnetic ink character reading device 10, the pulse width data string indicating the peak interval of the magnetic detection signal output from the magnetic head 21 is acquired. The character string printed on the paper 24 (magnetic ink character) is recognized based on the comparison result between the pulse width data sequence and the pre-stored reference pulse width data sequence for each magnetic ink character. The Since the magnetic ink character reader 10 does not recognize magnetic ink characters using the peak value of the magnetic detection signal output from the magnetic head 21, it is necessary to obtain data indicating the waveform of the magnetic detection signal output from the magnetic head 21. There is no. That is, it is not necessary to A / D convert the magnetic detection signal output from the magnetic head 21 by the A / D converter. As a result, the magnetic ink character reading device 10 can be realized with a relatively inexpensive configuration such as a comparator without using a relatively expensive A / D converter. According to the magnetic ink character reader 10, the magnetic ink character reader can be realized at a relatively low cost.

  Further, the magnetic ink character reader 10 recognizes a blank character between the magnetic ink characters by executing the processes of S119 and S120. That is, blank characters included in the character string printed on the paper 24 are recognized.

  The present invention is not limited to the embodiment described above.

  For example, the printing unit 15 is not an essential configuration.

  For example, the magnetic ink characters printed on the paper 24 may be magnetic ink characters in a format other than JIS X9002.

  Further, for example, when it is determined that reading of magnetic ink characters has failed, status information indicating that may be transmitted to the host computer via the interface 13.

  Further, for example, a magnetic ink character recognition process may be performed in consideration of a noise signal generated due to printing unevenness (void), mixing of motor noise or external noise, electrostatic discharge, or the like. FIG. 13 shows a signal output from the magnetic head 21 (b) and a differential amplifier 22a when the magnetic ink characters have uneven printing 40 (voids) as shown in FIG. An output signal (FIG. 3C) and a signal output from the magnetic detection signal processing circuit unit 22 (FIG. 4D) are shown.

When there is a printing unevenness 40 as shown in FIG. 13A, as shown in FIG. 13B, a signal (noise signal) indicating a magnetic change due to the printing unevenness 40 is magnetic between timings FG. Output from the head 21. In this case, as shown in FIG. 4D, a negative polarity pulse due to the printing unevenness 40 is output from the magnetic detection signal processing circuit 22 between the timings FG. That is, in the timings between E-G, is at the supposed positive polarity pulse originally width 2T is output one, positive polarity pulse (here, referred to as pulse 1.) Width T ₁ and a width T _{2 Three} pulses of a negative polarity pulse (referred to herein as pulse 2) and a positive polarity pulse of width T3 (referred to herein as pulse 3) are output.

  In order to deal with such a case, it is determined whether or not the width of each pulse is less than T, and if the width of the pulse is less than T, the pulse may be determined as a noise pulse. . Thus, for example, in the case shown in FIG. 13, the pulses 2 and 3 are determined as noise pulses, and the width of the original pulse 1 is equal to the width of the pulse 1 actually acquired. It may be determined that the width is added. Then, the width of the pulses 2 and 3 is added to the width of the actually acquired pulse 1, and the magnetic ink character recognition process may be executed. In this way, as long as the noise signal generated due to printing unevenness (void), motor noise or external noise, static electricity discharge, etc. is a signal having a time length less than T, the magnetic ink character by the noise signal is used. It is possible to suppress a decrease in reading accuracy.

It is a figure which shows the whole structure of the magnetic ink character reader which concerns on embodiment of this invention. It is a schematic diagram which shows the mechanism of a magnetic ink character reading part. It is a figure shown about an example of a magnetic ink character, and the signal output when a magnetic ink character is read. It is a functional block diagram of a magnetic detection signal processing circuit unit. It is a figure which shows an example of the circuit of a magnetic detection signal processing circuit part. It is a figure which shows the digital signal corresponding to each magnetic ink character. It is a figure which shows an example of a pulse width data sequence. It is a functional block diagram of the magnetic ink character reader which concerns on embodiment of this invention. It is a figure which shows an example of a reference | standard pulse width data sequence table. It is a flowchart which shows the process performed with a magnetic ink character reader. It is a flowchart which shows the process performed with a magnetic ink character reader. It is a flowchart which shows the process performed with a magnetic ink character reader. It is a figure shown about an example of a magnetic ink character, and the signal output when a magnetic ink character is read.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Magnetic ink character reading device, 11 Control part, 12 Storage part, 13 Interface, 14 Magnetic ink character reading part, 15 Printing part, 16, 16a, 16b Paper sensor, 17 Conveyance roller, 18 Conveyance motor, 19 Conveyance motor drive control Part, 20 magnet, 21 magnetic head, 22 magnetic detection signal processing circuit part, 22a differential amplifier, 22b, 22d differentiation circuit, 22c low-pass filter, 22e inversion circuit, 22f comparator, 23 timer part, 24 paper, 24a surface, 30 Peak interval data acquisition unit, 31 Reference peak interval data storage unit, 32 Comparison unit, 33 Recognition unit, 40 Printing unevenness.

Claims (4)

A magnetic head that outputs a signal corresponding to a change in magnetic flux caused by a magnetic ink character is provided, and a character string recorded on a recording medium using one or a plurality of magnetic ink characters is based on a signal output from the magnetic head. In the magnetic ink character reader to recognize,
Peak interval data acquisition means for acquiring peak interval data indicating a peak interval of a signal output from the magnetic head;
Reference peak interval data storage means for storing reference peak interval data in association with each magnetic ink character;
Comparison means for comparing peak interval data acquired by the peak interval data acquisition means with reference peak interval data stored in the reference peak interval data storage means;
Recognizing means for recognizing a character string recorded on the recording medium based on a comparison result by the comparing means;
A magnetic ink character reader. The magnetic ink character reader according to claim 1.
The recognizing unit includes a determining unit that determines whether a peak interval of a signal output from the magnetic head is equal to or greater than a predetermined interval, and recorded on the recording medium based on a determination result by the determining unit Recognizes whether the string contains whitespace,
A magnetic ink character reader. The magnetic ink character reader according to claim 1 or 2,
A means for outputting a signal based on a signal output from the magnetic head, and when a positive polarity signal is input from the magnetic head, a first voltage level signal is output from the magnetic head to a negative polarity. When a negative signal is input from the magnetic head, a signal having a second voltage level different from the first voltage level is output from the magnetic head to a positive polarity. Including signal conversion means for outputting until the signal is input,
The peak interval data acquisition means acquires data indicating each pulse width of the signal output by the signal conversion means as the peak interval data.
A magnetic ink character reader. A magnetic head that outputs a signal corresponding to a change in magnetic flux caused by a magnetic ink character is provided, and a character string recorded on a recording medium using one or a plurality of magnetic ink characters is based on a signal output from the magnetic head. In the control method of the magnetic ink character reader to recognize,
A peak interval data acquisition step for acquiring peak interval data indicating a peak interval of a signal output from the magnetic head;
Compare the reference peak interval data stored in the reference peak interval data storage means that stores the reference peak interval data in association with each magnetic ink character, and the peak interval data acquired by the peak interval data acquisition means. A comparison step to
A recognition step for recognizing a character string recorded on the recording medium based on the comparison result of the comparison step;
A method for controlling a magnetic ink character reading apparatus, comprising:

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