DE1913852U - ELECTROSTATIC RECORDING HEAD. - Google Patents

Description

; A.112106 * -U.65

DR. ING. H. THANK YOU

PATENT ADVOCATE

86 NETTER WAKI ₁ 41 FERNRTTi ¹ 36 74 28 TTNI) 36 41 15

1 SEflEBAPiTEST

0 6751 / 42g Gm

, March 2, 1965

OMITEOiriOS, IIC.

Elektros tatis rather record head

The subject of the innovation is an electrostatic recording head for recording writing tracks onto a recording medium with needle electrodes made of tungsten, which belong together in pairs and which are located in the vicinity of the End face of the recording head perpendicular to the Face, run parallel to each other and are isolated from one another, while further inside they diverge in a V-shape.

Such recording heads are predominant designed to record electrical signals on a moving tape, drum or disk. the The recording medium has a carbon-impregnated paper ?. layer on top of that with an insulating layer of plastic Material, e.g. polyethylene or yinyl, is coated. the Carbon impregnation of the paper makes it electrically conductive. This part of the paper generally becomes kept at ground potential. The electrodes are connected to a high voltage pulse circuit.

In a known recording head of this type, there are the electrodes in the vicinity of the end face largely

free, they have a great distance from each other and are

separated from each other by pieces of insulation that they do not touch. Such a recording head tends to have the location of electric discharge travels in the gap between the recording head and the recording medium, thereby failing the recording remains more linear

The object of the innovation is to eliminate the disadvantages mentioned, that is to say to provide a recording head where the migration of the electrical discharge does not occur · thereby It should be noted that due to the high-voltage pulses used, the risk of flashover is particularly great if the electrodes are arranged closer to each other. According to the innovation, the problem posed is achieved in that the needle electrodes are separated in the vicinity of the end face by a thin insulation layer on which they are in direct contact and together with the they are shed.

With such a close arrangement of the needle electrodes, wandering of the discharge gap is practically impossible, especially with The innovation also uses tungsten electrodes that are resistant to erosion, so that migration as a result of erosion is also avoided · The insulation layer prevents flashover.

There is another disadvantage of known recording heads in that the insulating material, e.g., epoxy resin or lime glass, which separates the needle electrodes has a tendency to be below that of the high temperatures generated by the electric charge melt or disintegrate. Insulating materials of this type also tend to

Absorb water, which increases the possibility of the high voltage pulses fail due to short circuit *

In a further embodiment of the innovation, this part of the tile is eliminated. that the insulation layer consists of a non-hygroscopic insulation material with a high melting point. Quartz is preferably used as the material. Finally, in a further embodiment, the rise in prices solves the problem of being able to write as many traces as possible with one recording head. Due to the close connection of the electrodes standing space is saved, can be accommodated in the other electrode pairs ₀ A recording head having a plurality of electrode pairs is characterized according to the innovation in that the mutually corresponding; Electrodes of the electrode pairs are arranged in one plane and that the electrodes of all electrode pairs are separated by the same insulating layer.

The following is an embodiment of the innovation shown in the drawing, in which it is a recording head acts with several pairs of electrodes is described. It shows:

Fig. 1 is a longitudinal section through the electrostatic recording head after the innovation,

FIG. 2 is an end view taken along line 2-2 of FIG. 1;

Fig. 3 is an enlarged partial representation of a rope of Fig. 2, ·

-4-

lig · 4 a section along line 4-4 of Fig. 3, fig «5 a section along line 5-5 of Jig. 4 and

ig. Figure 6 is a schematic representation of the electrical connections for the needle electrodes.

The drawings show an electrostatic recording head 10 according to the innovation, the number of high-voltage needle electrodes 11 »a number of grounded needle electrodes 12, needle holders 13 and 14, as well as an insulating layer 15, which separates the needle electrodes 11 and 12 · The needle holders 13 and 14 are with in the longitudinal direction extending grooves 16 or 17, in which the needle electrodes 11 and 12 are included. At one end of each of the needle electrodes 11 and 12, electrical conductors 18 and 19 are attached «.

The recording head 10 is assembled by inserting the white needle electrodes 11 or 12 made of tungsten into the respective ones Needle holder inserted and clamped in place by a suitable JOrmblock. Then the needle electrodes bound in place by potting the needle holders 13 and 14 with epoxy or other potting compound. At the parallel Needle electrodes 11 or 12 are attached to a quartz plate with a thickness of about 0.003 ". This quartz plate is then attached down machined to a thickness of about 0.0015 ". The other needle holder 13 or 14 is then attached to the other side of the quartz plate 15, so that the needle electrodes 11 and 12 are parallel to each other with a minimum distance. The end face 20 of the recording head 10 is then machined to a certain degree of smoothness. The final

Area 20 is a plane that passes through the free ends of the needle electrodes 11 and 12 and represents the recording area of the head 10.

The assembled needle holders 13 and 14 and the ladder and 19 are then placed in a suitable mold and encapsulated with epoxy resin, so that a unitary component of a suitable size arises. In Fig. 6 the electrical connections of the needle electrodes 11 and 12 are shown schematically. The high voltage electrodes 11 are connected directly to a pulse generator 21, and the electrodes 12 are connected to resistors 22 in series grounded. The pulse generator 21 provides output pulses with a size of about -2000 volts for each of the electrodes 11 for the following recording process to be described.

In Fig. 5, a part of the recording head 10 is enlarged shown, which is arranged immediately above a paper tape. The paper tape 23 consists of a plastic or insulating layer 24, e.g. made of polyethylene or vinyl, and a conductive layer 25, which are made with carbon or some other electrically conductive material is impregnated. The recording head 10 is positioned above the tape 23 so that the recording surface 20 is parallel to the top of the plastic layer 24 lies, however, by a few! thousandths Inches from it. The tape 23 is during the recording process moved past the recording surface 20 at a certain speed. The conductive layer 25 is usually kept at ground potential as they are held with metal rollers or metal guide pins that are connected to the chassis of the device.

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In operation, individual selected high-voltage needle electrodes 11 are supplied with negative high-voltage pulses in the order in which the signals are to be recorded Pulse is transmitted to the circuit, lies before the electrical discharge occurs, the entire voltage supplied by the pulse generator 21 at the gap 26 between the electrodes 11 and 12 · The potential difference across the resistor 22 is zero at this moment, since there is no current flows through it »The potential difference at the gap is sufficient to cause ionization of the air molecules in the gap, and an electrical discharge occurs. An electric current is then passed through the gap 26 by the ionized particles for as long as how the discharge continues what is of the width de r supplied pulses depends · The voltage at the gap 26 decreases significantly, and the greater part of the high voltage im-. pulse appears as potential or IR drop across the resistor 22 ₀ This means that the needle electrode 12, still with respect to the earth is at a fairly high negative potential "At the nip 26 developed negative ions are repelled · TiAl by this Porten and deposited as a static charge on the plastic layer 24 of the belt 23. The time required in this recording method is a few microseconds at the most. Accordingly, be information at very high speeds on the further moving belt 25 recorded ₀

The static charges applied to the insulating layer 24 can be made visible by the fact that the band 23 through a

The particles that make up the Ink powder are attracted by the static charge and adhere to the plastic layer. All loose powder is made from that The tape is removed, and the part attracted by the static charge is fixed by a thermal process or pressure. The resulting Coded information stored on the tape can either be given by a human or by a suitable reading machine will.

Extended by using tungsten needles for each of the electrodes The service life of the recording head increases significantly, as tungsten is able to withstand the high temperatures caused by the electrical discharge designed to withstand. Through the Installation of two separate needle electrodes, which are closely spaced are arranged, the tendency is reduced that the electrical discharge migrates laterally at the gap, so that the recorded · = · te information in the individual recording channels on the tape stays more precisely in line.

The resin layer between the charging electrodes acts as an insulating material also for the fact that the life of the recording head extended. The quartz has a high dielectric constant and withstands the high ones developed by the electrical discharge Temperatures. It is also not water-absorbent and therefore protects against a breakdown in tension that does not affect the Discharge gap occurs, or a failure of the electrodes due to Earzs

Claims (1)

eA.112106-t3.65 DR. ING. H. NEGBN THANKS PATENT ADVOCATE HAMBURG 3β · NEUER WALL 41 ■ ΙΙΪΚΪϋϊ 38 74 28 ΤΓΝΒ 38 41 15 TEUE GRAM ADDRESS I ΒΒΘΕΙΛΡATEWT 0MIG3E0NICS, INC. Protection claims 1. Electrostatic recording head for recording of writing traces on a recording medium with needle electrodes belonging together in pairs Tungsten, which are perpendicular to the end face in the vicinity of the end face of the recording head, parallel run towards each other and are isolated from each other, while they diverge further inside in a V-shape, characterized in that the needle electrodes (11, 12) in the vicinity of the end face (20) by a thin insulation layer (15) are separated, on which they lie directly and with which they are potted are· 2 x recording head according to claim 1, characterized in that the insulating layer consists s of a non hygroscopic insulation material having a high melting point (15) ^ ³ · 5. The recording head according to claim 1 or 2, comprising more than one electrode pairs arranged next to one another, characterized in that the electrodes corresponding to one another of the electrode pairs are arranged in one plane and that the electrodes of all electrode pairs through -2- the same insulating layer (15) are separated. 4. Recording head according to one of the preceding claims, characterized in that characterized in that the insulating layer (15) consists of quartz.