JPH10283697A - Magnetic information reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge a read-out failure of magnetic information on account of deterioration of magnetic force passing through a magnetic head by judging the level of the magnetic output of the data track of a photographic film updated by a detecting signal from an perforation sensor. SOLUTION: The peak value of a signal (b) from the magnetic head, detected by a peak detecting circuit 150 is reset by a signal (f) for each frame of the photographic film, outputted by a waveform shaping circuit 140 from an output P of the perforation sensor to become a peak signal (c) of each frame, and then to become an average signal (d) in the frame by a low pass filter 160. The signal (d) is compared with two set values VU and VL by a judging circuit 170, and when the signal (d) is between VU and VL, a decision is made that the magnetic output is deteriorated, and this decision signal (e) is outputted via a control circuit 180 to an alarm means 181. Consequently, an operator of the device can promote for cleaning of the magnetic head only when the magnetic output is deteriorated, thus working the device efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variety of photographs which are provided with a magnetic head for reading a recording signal from a photographic film on which information is magnetically recorded, and which amplify and process the read waveform to reproduce and use a digital signal. The present invention relates to a magnetic information reproducing apparatus used for data input in a processing device, an image input device, and the like.

[0002]

2. Description of the Related Art As a photographic system for easily exchanging information such as photographing conditions and printing conditions, a substantially transparent magnetic recording layer (hereinafter referred to as a photographic film magnetic layer) is provided outside an image area of a photographic film. There has been proposed a system in which information such as conditions and printing conditions is digitally recorded on a photographic film magnetic layer, and the photographic information is reproduced from the photographic film magnetic layer as a digital signal so as to be readable (International Application WO-90 / WO / 90). 04205, WO-90 / 04214,
US Patents USP-4965627, USP-49757
32).

[0003] The photographic film used in the current advanced photo system can be divided into an image area (hereinafter, referred to as a frame) and a non-image area in which a data track is formed. The non-image area can be distinguished into an upper non-image area where perforations are formed and a lower non-image area where no perforations are formed.The upper non-image area is provided with a data track for recording printing conditions and the like. The non-image area is provided with a data track for recording photographing conditions and the like. Both data tracks are recorded in one or a plurality of data blocks. Such a data block is version I
D and several data fields.

Accordingly, in a printing printer compatible with the advanced photo system, a magnetic head is brought into contact with a magnetic layer provided in a non-image area of a photographic film to take out a reproduction signal from a data track and convert the reproduction signal into bit data. A reading system for demodulating and reading serially is provided. According to such a system, the printing condition can be obtained by stretching the photographic conditions from the photographic film magnetic layer and reading it with a printing printer, thereby obtaining a print with good color tone and no failure. By digital recording, it is possible to obtain a print with good reproducibility when reprinting, and to automatically input data such as a photographing date and photographing conditions when taking a photographed film image into a computer.

[0005]

Generally, in a system which operates in a developing facility for processing a large amount of photographic film, dust and developer residue on the photographic film frequently accumulate on a magnetic head. In addition, if the thickness of scum and the like deposited on the magnetic head increases, the distance between the photographic film and the magnetic head increases, and the magnetic force passing through the magnetic head decreases, so that a stable output signal cannot be obtained. Therefore, a reading failure occurs. In the case of such a reading failure caused by deposits on the magnetic head, it can be improved by cleaning the magnetic head and adjusting the magnetic head and the photographic film to have an appropriate distance. It is conceivable to prompt.

However, photographed photographic film is
Even if magnetically recorded frames and unrecorded frames coexist, it is possible to detect frames that cannot be read out from unrecorded frames caused by, for example, unloading of a photographic film. If it cannot be determined whether the magnetic output is reduced due to the above deposits or the information is not recorded, even if the operator cleans it, it is useless.

An object of the present invention is to solve the above technical problems,
An object of the present invention is to provide a magnetic information reproducing apparatus capable of determining that a reading failure of magnetic information from a photographic film is caused by a decrease in magnetic force passing through a magnetic head.

[0008]

[Means for Solving the Problems]

(1) a magnetic head for reading a magnetic recording signal by contacting a data track provided on a photographic film, an amplifier circuit for amplifying a signal waveform read from the magnetic head,
In a magnetic information reproducing apparatus including a demodulation circuit for demodulating a reproduction signal from the amplification circuit into a digital pattern, a perforation sensor for detecting a perforation hole of the photographic film and a determination for determining a decrease in magnetic output of the data track. A magnetic information reproducing apparatus comprising: a circuit; and a warning unit for displaying or warning a result of the determination by the determination circuit.

(2) The magnetic information reproducing apparatus according to (1), wherein the input signal of the determination circuit is a signal updated by a detection signal from the perforation sensor.

(3) The magnetic information reproducing apparatus according to (1), wherein the judgment circuit has a plurality of judgment reference values.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 is a perspective view showing a mounted state of a perforation sensor according to the present embodiment, FIG. 2 is a block diagram showing a magnetic information reproducing apparatus according to the present embodiment, and FIG. 5 is a time chart illustrating signals of respective parts of the magnetic information reproducing device according to the embodiment.

The perforation sensor 142 is shown in FIG.
The perforation sensor 142 optically detects the presence or absence of the perforation hole 2 formed before and after the frame of the photographic film 1 shown in FIG. To obtain an output signal p. The signal p is subjected to waveform shaping by the waveform shaping circuit 140 so as to be easily processed, and the phase with the magnetic head is adjusted when the perforation sensor 142 and the magnetic head are not integrally formed as in the present embodiment. Used for The position of the frame separation of the photographic film is obtained from the output signal f.

The magnetic layer formed on the photographic film 1 includes:
In order to make the magnetic particles substantially transparent, the density of the magnetic particles dispersedly applied is extremely small, for example, about 1/100 as compared with a magnetic tape for audio or video recording or a digital information recording magnetic medium such as a floppy disk. It is small, so that light is not easily blocked by magnetic particles. Since the density of such magnetic particles is small, the magnetic energy to be recorded is weak, and the amplitude of the read signal is extremely small even if the magnetic head is wound as many times as possible. Such a small signal output (magnetic recording energy) deteriorates the signal-to-noise ratio of the residual noise of the amplifier circuit, the internal noise and the external noise, that is, the S / N ratio, and generates an error when demodulating the digital signal. Probability cannot be ignored.

Therefore, the magnetic information reproducing apparatus 100 according to the present embodiment employs a component and a circuit system such as an operational amplifier having a small residual noise in order to improve the magnetic information reproducing apparatus 100, and minimizes noise induction to the head winding. The electric and magnetic shielding is strictly performed, and a high-performance filter and a high-performance peak detection circuit usually used in higher-density digital data recording are employed. In the magnetic layer of the photographic film 1, recording is performed with a margin without increasing the linear density or track density of magnetic recording.

For convenience of explanation, the magnetic recording system in this embodiment is a pulse position modulation system in which a clock signal and data are represented by a pulse length, that is, a time. And magnetic recording of data magnetized as an S pole between the clocks. For example, if the data recorded between clocks is close to the preceding clock, it indicates data "1", and if the data recorded between clocks is close to the following clock, it indicates data "0".

[0016] Magnetic information reproducing apparatus 1 according to the present embodiment.
Reference numeral 00 denotes, for example, a magnetic head (not shown) for demodulating and reading out printing conditions and photographing information into digital signals from magnetic information on data tracks of a photographic film loaded in a printing printer, an amplification circuit 120, and a demodulation circuit 1.
30, a peak detection circuit 150 for detecting that the reading failure is a decrease in the magnetic force passing through the magnetic head, a low-pass filter 160, a determination circuit 170, the perforation sensor 142, the waveform shaping circuit 140,
It comprises a control circuit 180 and a warning means 181.
The configuration of each part will be described below.

A magnetic head (not shown) reads data recorded on a magnetic layer of a photographic film. The signal amplitude obtained from the magnetic head is usually several tens to 100 μV pp, although it depends on the film running speed. The magnetic signal detected by the magnetic head has a fluctuation including an increase in output due to variations in the characteristics of the film magnetic layer and the head, and a fluctuation in a direction in which the output decreases due to a spacing loss or an azimuth loss. Further, the signal obtained from the magnetic head includes the above-mentioned random noise. The signal B read from the magnetic head is amplified by an amplifier circuit 120, and the amplified signal is used as a demodulation circuit 13 for decoding recorded information.
0 and a peak detection circuit 150 for detecting the signal output
Sent to

The demodulation circuit 130 detects that the data pulse indicating either "1" or "0" is within the window width range of "1" or "0" even if the peak shift is caused by waveform interference or noise superposition. No demodulation error occurs. By estimating the case where the probability of the occurrence of a demodulation error increases, it is possible to estimate a total peak that appears to fluctuate with the peak position due to a decrease in the S / N ratio due to a decrease in the signal amplitude or a peak shift due to waveform interference due to an azimuth error. By the shift
This is considered to be the case where the window range exceeds “1” and “0”.

The peak detection circuit 150 has a peak value c of the amplitude of the signal b from the magnetic head amplified by the amplifier circuit 120.
Is detected. Peak value c is perforation sensor 1
Is reset by the signal f for each frame obtained by the low-pass filter 160 as a peak signal c for each frame.
To send to.

The low-pass filter 160 obtains an average signal output d within a frame by eliminating local fluctuations such as the diving noise of the peak detection circuit 150.

The judgment circuit 170 is a low-pass filter 160
The result of comparison between the average output d from the two and the two set values _VU and _VL is sent to the control circuit 180. These two set values V _U
And V _L are used to determine whether the cause of the signal amplitude decrease is clogging of the head gap. For example, the magnetic output when ideal recording and reproduction are performed with the photographic film and the magnetic head in close contact with each other. as the 0 dB, normal ones magnetic output is higher than -6dB output, and reduced output to -20dB from -6dB, when unrecorded a lower than -20dB, the two settings -6dB as V _U, V -2 as _L
0 dB. However, since the set value is determined by the S / N ratio of the reproducing apparatus, the set value is not limited to the numerical value shown in this embodiment. The compared outputs are sent to the control circuit 180 using the logical product output of the determination results as the determination signal e.

In the embodiment, the determination of the magnetic output from the magnetic head is performed using two set values. However, the determination may be performed based on one or two or more set values.

The control circuit 180 determines a normal output, a reduced output, and no recording for each frame in the photographic film based on the determination of the magnetic output from the determination signal e and the signal f for each frame. If the magnetic output decreases due to the accumulation of dust etc. on the magnetic head, the decrease in magnetic output in a single frame is small, and occurs in multiple frames or multiple photographic films. Depending on the frequency, the control circuit 180 sends a control signal to the warning means 181 to request the operator of the apparatus to clean the magnetic head.

The above is the description of the magnetic information reproducing apparatus 1 of the present embodiment.
00 is a schematic configuration.

Next, the reproducing operation of the magnetic information reproducing apparatus according to the present embodiment will be described with reference to FIG.

FIG. 3A shows an output signal b from the amplifier circuit 120 by a solid line, and an output signal c from the peak detection circuit 150 by a dotted line.

The output signal b is a signal which is read from a data track recorded at a predetermined interval, for example, a clock magnetized at the N pole and a data track magnetized on the S pole as data between the clocks. ), A pulse falling to the negative electrode (-) between the rising pulse and the rising pulse is indicated by a solid line. It can be seen that the output signal b shows that the rising pulse and the falling pulse gradually decrease the peak level due to the decrease in the magnetic force passing through the magnetic head.

The output signal c indicates a signal detected from the positive peak of the signal b. As described above, it can be seen that the output signal b gradually decreases as the peak level of the output signal b decreases.

FIG. 3B shows the output signal d, which is an input signal of the decision circuit 170, and the set values V _U and V _L of the decision circuit 170. The output signal d is a signal from which the local variation of the output signal c has been eliminated by the low-pass filter 160, and is shown by a solid line. Therefore, the determination circuit 170 will be the output signal d set value V _U, the process of comparison between a V _L.

FIG. 3C shows an output signal e from the determination circuit 170. The output signal e becomes a high level when the output level of the output signal d is between the set value _VU and the set value _VL . The output signal e is supplied to the control circuit 1
80 input signals.

The magnetic information reproducing apparatus 1 according to the present embodiment
As described above, since the magnetic output is determined for each frame as described above, the operator of the apparatus is prompted to clean only when the magnetic output is reduced, so that the apparatus can be operated efficiently.

(Embodiment 2) FIG. 4 is a block diagram showing a magnetic information reproducing apparatus according to another embodiment.

The same parts as those in FIG. 1 of the first embodiment are denoted by the same reference numerals, and their operations are also the same, so that detailed description will be omitted.

The magnetic information reproducing apparatus 100 according to the present embodiment
Are the peak detection circuit 150, the low-pass filter 160, and the determination circuit 17 used in the device described in the first embodiment.
By connecting the A / D converter 260 instead of 0, the magnetic output level can be converted into digital data and the control circuit 180 can directly read the magnetic output level.
The determination can be performed with higher accuracy than the comparison using the fixed set value according to the first embodiment.

As described above, the magnetic information reproducing apparatus according to the present embodiment determines the magnetic output for each frame and prompts the operator of the apparatus to perform cleaning only when the magnetic output is reduced. Operation can be performed efficiently.

[0036]

According to the magnetic information reproducing apparatus of the present invention having the above-described structure, the magnetic output is determined for each frame, so that even when unrecorded frames are mixed, only when the magnetic output decreases. Since cleaning is encouraged, the operation of the apparatus can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an attached state of a perforation sensor according to the present embodiment.

FIG. 2 is a block diagram illustrating a magnetic information reproducing apparatus according to the present embodiment.

FIG. 3 is a time chart showing signals of respective parts of the magnetic information reproducing apparatus according to the present embodiment.

FIG. 4 is a block diagram showing a magnetic information reproducing apparatus according to another embodiment.

[Explanation of symbols]

 Reference Signs List 120 amplifying circuit 130 demodulating circuit 140 waveform shaping circuit 142 perforation sensor 150 peak detecting circuit 160 low-pass filter 170 determining circuit 180 control circuit 181 warning means

Claims (3)

[Claims] A magnetic head for reading a magnetic recording signal by contacting a data track provided on a photographic film;
In a magnetic information reproducing apparatus including an amplifier circuit for amplifying a waveform of a signal read from the magnetic head and a demodulation circuit for demodulating a reproduced signal from the amplifier circuit into a digital pattern, a perforation hole of the photographic film is detected. A magnetic information reproducing apparatus comprising: a perforation sensor; a determination circuit for determining a decrease in magnetic output of the data track; and a warning unit for displaying or warning a determination result of the determination circuit. 2. The magnetic information reproducing apparatus according to claim 1, wherein an input signal of the determination circuit is a signal updated by a detection signal from the perforation sensor. 3. The magnetic information reproducing apparatus according to claim 1, wherein the determination circuit has a plurality of determination reference values.