DE2323484A1 - REGISTRATION AND WRITING DEVICE - Google Patents

Description

R. 1 46 2

March 22, 1973 Fb / Fm

Attachment to the patent application

ROBERT BOSCH GKBH, Stuttgart Registering and writing instrument

The invention relates to a registering and writing device in that on a burn-out metal coating of a recording medium a plurality of mutually insulated writing electrodes rest on the surface parts by applying an electrical voltage burn out of the metal coating of the recording medium moved under the writing electrodes.

In such devices, the recording medium (RMP tape) is almost always transported in the same direction, so that Burn-out residues and the constantly lying writing Electrodes stick scraped metal particles from the metal coating on the writing electrode tips and form an oxide beard. Due to this oxide bit, which is electrically conductive, the writing electrodes, which are arranged with a small spacing next to one another, can e.g. for plain text and so-called punched tape recorders, be short-circuited. In such a case, the metal coating of the recording medium is inadmissible under the two short-circuited writing electrodes burned out.

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The invention is based on the object of rendering short-circuit bridges between the writing electrodes harmless by simple means. j

According to the invention this object is achieved in that the writing electrodes by a switching device during the Writing time on a burn-out voltage and in the writing breaks are connected to ground. In a further development of the invention, one of each between two adjacent writing electrodes can them insulated, permanently connected auxiliary electrode arranged be.

In the drawing, the subject of the invention is based on two Exemplary embodiments shown. They show in spatial representation:

1 shows the writing head of a plain text writer with the writing electrodes connected to a switching device;

Pig. 2 the print head of a punched tape recorder with between auxiliary electrodes arranged on the writing electrodes.

lig. 1 shows the write head 20 for a plain text writer with several juxtaposed writing electrodes 21, which are isolated from each other by thin layers of mica. A tape 22 made of metal recording paper is placed under the writing electrodes 21 passed in the direction of the arrow, its metal coating is connected to ground via a wide electrode 23. That Belt 22 runs over a pad 24 through which it is the required pressure is printed against the ends of the ground and writing electrodes. To short-circuit bridges harmless to make, which by the deposition of electrically conductive residues

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stand between the writing electrodes 21 can arise, these are in the writing pauses by an electronic Switching device 25 connected to ground. An electrically conductive bridge 28 is now formed between two neighboring ones Writing electrodes 21, then flows when a negative burnout pulse is applied to one of the two writing electrodes 21 a current to the neighboring, non-writing writing electrode. The then via the switching device 25

is the short-circuit current flowing to ground

limited so that it burns away the bridge 28 without, however, maintaining an arc between the two writing electrodes 21. So that the writing electrodes 21 are not caused by dust deposits or by metal particles of larger cross-section are short-circuited, the end face of the writing electrodes 21 is covered with an insulating layer 27 made of mica Covered so far that only a narrow end portion of the electrode face remains free.

Is the distance between the adjacent writing electrodes larger than 0.5 mm, then an auxiliary electrode which is permanently connected to ground is inserted between every two writing electrodes. Such an arrangement is shown in FIG. It shows a writing head 30 for a punched tape writer with nine writing electrodes 31 and the narrow auxiliary electrodes 32, which by mica layers against the writing electrodes 31 are isolated. All of the auxiliary electrodes 32 are with each other electrically connected and grounded.

The metal paper tape 34 initially runs with its metal coating under a ground electrode 35 through over a base to the write head 30, the writing electrodes 31 of which are from a electronic switching device 37 in such a way to a negative Voltage in relation to the metal coating of the recording medium gers are placed that the resulting burns 38 in the Metal coating of the metal paper tape 30 represent information encrypted according to any code.

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Forms, "when operating the tape recorder now a electrically conductive bridge 39 between writing and auxiliary electrodes, so it is burned away by a course fault current. It is also expedient for this electrode arrangement the writing electrodes 31 in. The writing pauses are connected to ground.

_ c

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Claims (2)

Claims · . ί i.j.Registering and writing device in which several writing electrodes, insulated from one another, rest on a burn-out metal coating of a recording medium, which when an electrical voltage is applied burn out parts of the surface of the metal coating of the recording medium moving under the writing electrodes, characterized in that the writing electrodes (21, 31 ) are connected to a burn-out voltage during the writing time and to ground during the writing pauses by a switching device (25 »37). 2. recording and writing device according to claim .1, characterized in that that in each case between two adjacent writing electrodes (31) one of them is isolated and permanently connected to ground Auxiliary electrode (32) is arranged. 409847/0639 Blank page