JPS6139906A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain recording/reproducing with excellent S/N by arranging an erasure head at a position in preceding over a recording or a recording/reproducing head and providing a means driving the erasure head at recording/reproduction in a timing earlier than that of the recording/reproducing head. CONSTITUTION:A magnetic recording medium 5 is, e.g., a floopy disc and driven in the direction of arrow 4. A control section FDC is a host controller provided at the outside of a device main body FDD, a signal detected from a medium 5 by a recording/reproducing head 2 at reproduction is fed via a reproduction circuit 11 to control the FDD according to the time chart. When an area to be recorded is discriminated by a signal detected from the recording medium 5 via the recording/reproducing head 2, a write gate signal WG is generated and ahead it, an erase head signal EG is generated. When the EG is generated, a gate 13 is opened and an erasure current is fed to an erasure head 3. Since a part on which the recording/reproducing head 2 records new information is erased already by an erasure head 3, no overlapped written part is caused and no preceding information is mixed to the reproduced output.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] □ The present invention relates to a magnetic recording/reproducing device, and particularly to a drive method for an erasing head.

[Technical background of the invention and its problems]

In magnetic recording and reproducing devices that perform digital recording and reproducing using magnetic recording media such as floppy disks, digital recording is basically saturated magnetic recording, so new information is generally not recorded on tracks that have already been recorded. When recording, new information is simply overwritten on the track. However, with this method, even if new information is overwritten, the previous information may not be completely erased, resulting in an increase in so-called overwriting noise, and errors in the positioning of the recording head or recording/playback head relative to the track. If this happens, part of the previous information will remain at the end of the track without being rewritten with new information, and this will cause a problem in that it will be mixed into the reproduced output as noise during reproduction.

Therefore, in magnetic recording and reproducing devices for digital recording, a position that precedes the recording head or the recording/reproducing head on the magnetic recording medium, that is, on the rear side in the running direction of the magnetic recording medium, is placed at a position that is wider than the width of the recording head or the recording/reproducing head in the track direction. By arranging an erasing head with a large width in the track direction,
Prior to recording, it may be possible to erase information that has already been recorded. However, even when such an erasing head is used, there is a physical distance between the recording head or recording/playback head and the erasing head, especially at the start of recording, so the previous information is erased by a length corresponding to this distance. Some parts will remain that will not be erased. In this unerased area, new information is overwritten on the previous information, resulting in overwriting noise.Furthermore, due to positioning errors of the recording or recording/playback head relative to the track, the previous information remains unerased, causing noise to be mixed into the playback output. I will do it.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording/reproducing device that can prevent overwriting noise from occurring over the entire track section including the start of recording, and from increasing noise in the reproduction output due to head positioning errors. It is in.

[Summary of the invention]

The present invention provides a magnetic recording/reproducing device in which an erasing head is disposed at a position preceding a recording head or a recording/reproducing head on a magnetic recording medium. It is characterized by having means for driving at an earlier timing.

〔Effect of the invention〕

According to the present invention, since the previous information can be completely erased in advance by the erasing head even in the recording start part, new information can be recorded by the recording head or the recording/playback head. never occurs. Therefore, the conventional problems of overwriting noise and previous information being mixed into the playback output due to positioning errors of the head with respect to the track are eliminated, and the playback output is of high quality with a high S/N ratio over the entire track section. It becomes possible to obtain.

(Embodiment of the Invention) FIG. 1 shows the arrangement of a magnetic head in an embodiment of the present invention, in which a recording/reproducing head 2 is arranged for a track 1, and furthermore, this recording/reproducing head 2 is placed on a magnetic recording medium.
The erasing head 3 is disposed at a more advanced position, in other words, at a position on the rear side of the magnetic recording medium in the traveling direction indicated by an arrow 4. The erasing head 3 is located in the gap 2a of the recording/reproducing head 2.
The gap 3a has a width larger than the width of the gap 3a. At the start of recording, the erasing head 3 is driven at a timing earlier than the recording/reproducing head 2, as will be described later.

FIG. 2 shows the configuration of the portions related to the present invention of a magnetic recording/reproducing apparatus including the above-mentioned recording/reproducing head 2 and erasing head 3. As shown in FIG. The magnetic recording medium 5 is, for example, a floppy disk, and rotates in the direction of the arrow 4. The control unit (FCC) is the floppy disk device body (FDD)
During recording, the signal detected from the magnetic recording medium 5 by the recording/reproducing head 2 is supplied via the reproducing circuit 11, and based on the signal, the FDD is operated according to the time chart shown in FIG. control. That is, from the magnetic recording medium 5 to the recording/reproducing head 2
Area (sector) to be recorded from the signal detected through
When it is determined, a write gate signal WG is generated, but
Prior to that, an erase gate signal EG is generated. When the erase gate signal EG is generated, the gate 13 is opened and a DC or AC erase current is supplied to the erase head 3 via the driver 16. Next, Light Gate Shin@WG
, write data (information signal>WD) are sequentially generated, and the write data WD is supplied to the recording/reproducing head 2 via the gate 12 and driver 15.

The logic circuit 14 controls the timing of the entire FDD, and the driver 17 drives the mechanical system of the FDD.

By driving the erasing head 3 earlier than the recording/reproducing head 2 prior to new recording in this manner, the above-mentioned conventional problem is solved. This will be explained with reference to FIG. Fourth
Figures (a) and (b) show a recording/reproducing head 2 and an erasing head 3.
each gap 2a.

3a shows the state on the magnetic recording medium when it moves from the position of the broken line to the position of the solid line, 21 is the previous information that has already been recorded, and 22 is the new information that has been newly recorded. It is. That is, when the erasing head is driven at the same time as the recording/reproducing head as in the conventional case, as shown in FIG. A portion corresponding to the length that is not erased by the erasing head 3 is created.

In this portion 22a, since the new information 22 is overwritten on the previous information 21 as described above, overwriting noise occurs.

Further, if there is a positioning error of the head with respect to the track, a part 21a of the previous information 21 will remain on the side of the part 22a without being rewritten as new information 22, and this will be mixed into the reproduced output as noise.

On the other hand, if the erasing head 3 is driven first as in the present invention, the part where the recording/reproducing head 3 records new information is already erased by the erasing head 3 even at the start of recording. As shown in b), there is no overwriting of the new information recorded by the recording/reproducing head 2, and even if there is a positioning error of the head with respect to the track, when reproducing the newly recorded part, Previous information is not mixed into the playback output.

In this way, according to the present invention, it is possible to perform recording and reproduction with a good S/N ratio and excellent reliability.

It should be noted that the present invention is not limited to the embodiments described above, and for example, although the recording/reproducing head and the erasing head are integrally constructed in the embodiment, they may be constructed separately. Further, the recording head and the reproducing head may be provided separately. In this case, the erasing head only needs to be in a position preceding the recording head on the magnetic recording medium, and the positional relationship between the reproducing head and the erasing head is not particularly limited.

Furthermore, in the embodiment, the case of a magnetic recording and reproducing device using digital recording using a floppy disk was explained.
It goes without saying that the present invention can also be applied to magnetic recording and reproducing devices that record and reproduce audio or video signals in an analog manner. In addition, the present invention can be modified and implemented in various ways without departing from the scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the arrangement of a magnetic head in an embodiment of the present invention, FIG. 2 is a configuration diagram of the main part of a magnetic recording and reproducing apparatus according to an embodiment of the present invention, and FIG. Time charts for explaining the operation, Figures 4(a) and 4(b) show recording states when the erasing head and recording/playback head are driven simultaneously at the start of recording, and when the erasing head is driven at a timing earlier than the recording/playback head. FIG. 1... Track, 2... Recording/playback head, 3...
Erasing head, 5... Magnetic recording medium (floppy disk), 10... Control section, 21... Previous information, 22.
...New information. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] In a magnetic recording/reproducing device in which an erasing head is disposed at a position preceding a recording head or a recording/reproducing head on a magnetic recording medium, the erasing head is moved from the recording head or the recording/reproducing head at the start of recording on the magnetic recording medium. A magnetic recording/reproducing device characterized by being equipped with means for driving at an early timing.