JPH0433592Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a magnetic reading device, such as an automatic ticket inspection device, in which two reading heads, upper and lower, are arranged in a ticket conveyance path.

As shown in FIG. 1, two magnetic reading heads 3 are installed in the ticket conveyance path 1 of the automatic ticket inspection device so that the information recorded on the ticket 2 can be read no matter which direction the ticket 2 is inserted. , 4 are arranged above and below. The reading heads 3 and 4 are separated by a distance of 2 l in the transport direction, and the upper head 3 is located further back than the lower head 4 in the transport direction. The distance 2l is shorter than the length of the ticket 2. A ticket detector 5 is also arranged behind the upper head 3. This detector 5 is constituted by a photoelectric detector.

FIG. 2 shows the reading circuit. The outputs of both the upper and lower heads 3, 4 are sent to a switching circuit 12 via an amplifier 11, respectively. The switching circuit 12 is the counter 1
4 and the operation of a D flip-flop 15 based on timing pulses from the detector 5. The signal that has passed through the switching circuit 12 is waveform-shaped by a slice circuit 13 and sent as read data to a processing circuit (not shown).

There is a start code at the first position of the data magnetically recorded on the ticket 2. This start code consists of 4 bits, and when read, 4 pulses are obtained. On the other hand, in order to make the distance 2l between the upper and lower heads 3 and 4 as short as possible, the switching circuit 12 is normally switched to pass the read signal from the upper head 3. When the leading edge of the ticket 2 reaches the intermediate position A between the heads 3 and 4, if the 4-bit start code has already been read by the upper head 3, the read signal from the upper head 3 is used as data. , if the start code is not read, it switches to the lower head 4.

Counter 14 produces an output when it counts four bit start codes. The output of the counter 14 is input to the data input terminal D of the D flip-flop 15. The ticket detection signal of the detector 5 is delayed by a timer (not shown) or the like, and when the leading edge of the ticket 2 reaches position A, a timing pulse is input to the clock input terminal T of the D flip-flop 15. When the timing pulse is input, if there is an output from the counter 14, the output Q of the D flip-flop 15 goes to H level, and if there is no output from the counter 14, the output Q goes to L level.

In such a magnetic reader, a relatively long distance of 2 liters must be maintained between the upper and lower heads 3 and 4, which increases the length of the reader and, as a result, requires a longer ticket transport path. I have no choice but to. In addition, if there is no magnetically recorded data on the front half of the ticket and data is recorded only on the rear half as shown by B in Figure 1, even if the data recording side is on the upper side. Even when the leading edge of the ticket 2 reaches position A, the start code reading signal is not output from the upper head 3, so it is switched to the lower head 4, and the data on the ticket cannot be read.

This idea was made in view of the above circumstances,
To provide a magnetic reader capable of reducing the size of a reading unit by shortening the distance between upper and lower reading heads, and also capable of reliably reading data even when data is recorded only on a part of a ticket. It is something.

This idea is based on a circuit that slices the read signal of each read head at the required level in a magnetic reader in which two read heads, an upper and a lower read head, are arranged on the transport path of a magnetic recording medium on which data is magnetically recorded on one side. , and a start detection circuit for detecting the required start bits recorded on the recording medium from the outputs of these slice circuits. Each of the above slice circuits has two slice levels, high and low. The high slice level is set to a level lower than the peak level of the normal read signal of the read head and higher than the peak level of the read-behind signal, and the lower slice level is set to a level lower than the high slice level mentioned above. is set to . In the initial state, both slice circuits are set to a high slice level,
Based on the detection signal from the start detection circuit, the slice level of the corresponding slice circuit is switched to a lower slice level. Read data is then output from the slice circuit whose slice level has been switched.

Therefore, it is no longer necessary to arrange the upper and lower reading heads at intervals, and the length required for reading in the transport path can be minimized. Furthermore, even if data is recorded only on a portion of the ticket in the transport direction, this data can be read accurately. Furthermore, since the slice level of the slice circuit corresponding to the start detection circuit that outputs the detection signal is switched to a lower slice level, it is also possible to improve the reading rate for magnetic recording media whose magnetic output has decreased. .

Hereinafter, an embodiment of this invention will be described in detail based on FIGS. 3 and 4.

In FIG. 3, the read signals of the upper and lower heads 3 and 4 are sent to separate slice circuits 21 and 22 via an amplifier 11, respectively. slice circuit 21,
22 each have two different slice levels L1 and L2 as shown in FIG. The high slice level L1 is the peak of the read signal of the recorded data (shown by the solid line in FIG. 4, this is called the normal signal) when data is magnetically recorded on the side of the ticket 2 facing away from the head. A signal due to magnetism that is lower than the level and leaks to the head through the ticket when data is magnetically recorded on the opposite side (shown by the broken line in Figure 4, this is the back-reading signal) ) is set to a higher level than the peak level of Low slice level L
2 is set to a required level lower than level L1.

The output signals of the slice circuits 21 and 22 are sent to an OR circuit 25 and counters 23 and 24, respectively. The output of the OR circuit 25 becomes read data. Counters 23 and 24 each count a 4-bit start code and generate an output when four pulses are counted. counter 23,2
The outputs of 4 are sent to slice circuits 21 and 22, respectively. The slice levels of the slice circuits 21 and 22 are initially set to a high level L1, and when the output signals of the counters 23 and 24 are input, the slice levels change to a low level L2.
Changes to The counters 23 and 24 are reset by a signal indicating that the ticket has been read or a signal indicating that the ticket has passed through the heads 3 and 4.

When the ticket 2 is conveyed with the data recording surface facing upward, the upper head 3 reads the regular start code, and the read signal b is output from the slice circuit 21. When the counter 23 counts these four pulses, the counter 23 generates an output c, and the level of the slice circuit 21 changes from L1 to L2.
As the ticket 2 is conveyed, the upper head 3 sequentially outputs a read signal a, which is sliced at level L2 and fed to the OR circuit 25.
and becomes the read data.

Circuit 22 for slicing the read signal of the lower head 4
Initially, slice level L1 is set. However, since the read signal of the lower head 4 is a back-read signal, it does not reach the slice level L1, and the four pulses of the start code are not output from the slice circuit 22. Therefore, the slice circuit 22
The slice level remains at L1, and no read data is output from the slice circuit 22.

When the reading of the ticket is completed, the counters 23 and 24
is reset, and the slice circuits 21,
22 slice levels return to L1.

[Brief explanation of the drawing]

1 and 2 show a conventional example. FIG. 1 is a block diagram showing the arrangement of the reading head, FIG. 2 is a block diagram of the reading circuit, and FIG. 3 is a block diagram showing an embodiment of this invention. FIG. 4 is a waveform diagram showing the output signal of the block of FIG. 3. 1...Ticket conveyance path, 2...Ticket, 3, 4...Reading head, 21, 22...Slice circuit, 23, 24
...Counter, 25...OR circuit.

Claims (1)

[Scope of utility model registration request] In a magnetic reading device in which two reading heads, an upper and a lower reading head, are arranged on a transport path of a magnetic recording medium on which data is magnetically recorded on one side, a circuit that slices the read signal of each reading head at a required level,
and a start detection circuit that detects the required start bits recorded on the recording medium from the outputs of these slice circuits, and each of the slice circuits described above has two slice levels, high and low. is set to a level lower than the peak level of the normal read signal of the read head and higher than the peak level of the read-behind signal, and the lower slice level is set to a level lower than the higher slice level mentioned above. In the initial state, all slice circuits are set to a high slice level, and based on the detection signal from the start detection circuit, the slice level of the corresponding slice circuit is switched to a low slice level, and the slice level A magnetic reading device in which read data is output from a slice circuit that is switched.