DE1120717B - Pen for creating traces of writing by applying an electrical potential to metallized recording media - Google Patents

Description

Pen for creating traces of writing by the action of a electrical potential on metallized recording media for registration processes Metallized recording media are often used, from their metal coating a writing trace by means of an electric current through a writing electrode burned out or a trace of writing on its metal coating with a heated pen is produced.

Turns for the pen sliding on the recording medium up to now, tungsten, molybdenum or a chromium-nickel alloy have been used. This for the Metals used in writing pencils have the property that they are used during the writing process can be attacked by the effects of heat over time. The writing tip is corroded and for this reason wears out extremely heavily. Also forms around the A roughened tip of the writing point attacked and roughened by the corrosion, a beard of the burnt-out one Metal of the recording medium. Some of those previously used for the pen Metals tend to get in contact with the burned out metals of the recording medium alloy so that the writing tip thickens in an impermissible manner. These Changes in the writing tip cause an intermittent, indistinct and smeared appearance Trace. In addition, the nib becomes dirty and deformed the friction between pen and recording medium increases significantly and exposed to strong fluctuations, so that the writing sensitivity of the recorder is significantly reduced and gives rise to measurement errors.

To remedy the defects listed and a clean, clear trace of the writing To ensure with low, constant friction, exists according to an earlier one Proposal of the electrical and the in contact with the recording medium The head of the pen, which is designed as a writing electrode, is held with good thermal conductivity from a known manner by alloying or sintering one or more heavy metals the V. to VII. subgroup of the periodic system, z. B. tungsten, molybdenum, tantalum, Rhenium, made with refractory precious metals, preferably the platinum group Material or from one or more conductive ones by alloying or sintering Salts of the heavy metals mentioned, such as. B. of carbides, borides, nitrides, with high-melting points Precious metals, preferably the platinum group, produced material.

It has now been shown that here and there, in particular when using recording media with cadmium or aluminum as metallization material, after a long period of operation, the burned-out metal of the recording medium on the Pen sticks and forms a beard that affects writing accuracy. In order to prevent or prevent the burnt-out metal from sticking in these cases as well. To reduce it to a non-disruptive level is, according to the invention, that with the recording medium in contact with the head of the pen designed as a writing electrode made of a material composed of one or more conductive salts, e.g. B. the carbides, borides, nitrides, the heavy metals of the V. to VII. Subgroup of the periodic table, e.g. B. tungsten carbide, molybdenum carbide, tantalum carbide, rhenium carbide, consists.

When using such a material results from the use Conductive salts of the metals mentioned do not have an adhesive effect on the burned-out metal of the recording medium on the pen, so that it can also be used for long periods of operation a perfectly clean trace is guaranteed.

Alloys with a very high hardness are known for spring tips. There these nibs are used for writing organs that serve as an ink pen, they must be resistant to chemical attack by the writing fluid while in the pen according to the invention, the head of the pen, in which a Write trace due to the action of an electrical potential on metallized recording media is generated, should not be attacked electrically.

As far as sintered platinum alloys with additives up to 3011 / o der Platinum group metals and heavy melting oxides of base Metals are known, these alloys are used for operations in which Temperatures of 1000 ° C and higher occur, or in cases where corrosive Influences occur, among which metals produced in the usual way one Recrystallization or coarsening of the structure or other deterioration subject to weakening of mechanical properties such as strength or hardship, 'would affect. The main areas of application are: Catalysts for oxidation of ammonia to nitrogen oxides, tools or other apparatus for Manufacture and treatment of flowing molten glass and thermocouples, Furnace heating elements, catalytic wire nets, chemical apparatus, the manufacture of spark plug electrodes and the like.

For a pen to create traces of writing through action an electrical potential, the known alloys are completely unsuitable, since this would cause metal migration and burn-off that would cause sliding with a lot make small friction impossible.

There are also writing electrodes known that are used for recording Thermal effect are used and where great mechanical, chemical and in particular thermal resistance is required. In the invention is by high electrical and thermal conductivity of the pen just taken care of that caused by the electric field between the pen and the metallized recording medium resulting heat is dissipated well and quickly.

The pen according to the invention is one those that slide on the recording medium with extremely weak friction should in order to achieve a high level of writing sensitivity. The formation of the writing trace is caused by a voltage between the pen and the recording medium caused the arcing when the pen glides very easily or short arcs are generated at the point of contact, through which the metal evaporates. The trace is not created by heating the pen, but by the electric field between the pen and a thin layer of metal. Therefore are not the most important requirements for the pen in the first place low mechanical wear and high chemical resistance, but high resistance Against the electrical attack of material by electrical heat, sparks or short arcs and against the build-up of vaporized material on the writing tip. It must therefore the high temperature of several 1000 ° C occurring at the point of contact, for example 3000 to 7000 ° C, can be quickly removed through the holder of the pen, the head can withstand these temperatures without changing the smooth surface got to. The material on the head must have a high melting and boiling temperature and most importantly great resistance to sputtering, as well as good conductivity and good metallic properties Connected to the pen holder. The writing material is also not allowed Tends to stick and weld to the metal of the recording medium, no roughening through Get material migration and burn-off. Furthermore, it is allowed to be vaporized or burned Do not place the metal of the recording medium on or with the writing tip alloy themselves. A chemical change of the writing surface due to high heat is allowed do not occur.

Another material improvement z. B. in terms of the increase the hardness is achieved according to a development of the invention, if in addition one or more conductive salts, e.g. B. carbides, borides, nitrides, metals the fourth main or subgroup of the periodic system, such as titanium carbide, silicon carbide or the like., can be used. By charring, i.e. superficial burning in of Carbon, the suppression of the adhesive effect can be further improved. The high-melting salts can still be used for alloying or sintering Precious metals, e.g. B. carbides, preferably rhodium, iridium, osmium, ruthenium, as well boron carbide can also be used advantageously. The components of the pen material can expediently be manufactured and sintered by powder-ceramic methods. she can be used both without any additional binders or with small admixtures base metals, e.g. B. nickel, chromium, cobalt, copper, indium, cadmium or beryllium, or noble metals such as gold, palladium, platinum.

The following compositions are given as an example of a pen according to the invention, the material of which, in addition to the salts of the heavy metals mentioned, also contains salts of main or subgroup IV of the Periodic Table, the numbers shown under the relevant chemical abbreviations indicate the proportion in percent by weight: Salts of the salts of the fourth main group or subgroup Heavy metals of the periodic table WC or WB Ti c or si C 50-80 20-50 90-99 1-10 If salts of the heavy metals mentioned and salts of the noble metals mentioned are used, the following composition can be selected: Salts of Heavy metals Salts of precious metals WC or WB Rh C or Rh B 75-98 2-25 If the material consists of three components, the following composition should be mentioned: Salts of the IV main Salts of the or subgroup salts Heavy metals of the periodic of precious metals Systems WC or WB Ti C or Si C Rh C or Rh B 50-70 15-25 15-25 In the drawing, an embodiment of a recording device equipped with the pen according to the invention is shown schematically. The metallized recording medium 1 is guided over the two rollers 2 and 3. Above the roller 3, the pen 4, designed here as a writing electrode, presses, for example by means of a spring 5, on the metallized recording medium 1. The writing voltage U is applied to the roller 2 and the writing electrode 4. The writing electrode 4 is under the influence of a measuring device (not shown) and deflects according to the measured values. The writing electrode 4 consists of a material proposed according to the invention for the writing electrode, for example tungsten carbide or boride or an alloy, for. B. from WC and Ti C.

Claims (5)

PATENT CLAIMS: 1. Pen for generating writing traces by the action of an electrical potential on metallized recording media; characterized in that the standing with the recording medium in contact with the head of the electrode formed as a writing stylus is made of a material selected from one or more conductive salts, z. B. the carbides, borides, nitrides, the heavy metals of the V. to VII. Subgroup of the periodic system, z. B. tungsten carbide, molybdenum carbide, tantalum carbide, rhenium carbide. 2. Pen according to claim 1, characterized in that at least the one with the recording medium in contact with the head of the pen designed as a writing electrode consists of a material that by alloying or sintering one or more conductive salts, e.g. B. the carbides, borides, nitrides, the heavy metals of the V. bis VII. Subgroup of the Periodic System and one or more conductive salts, z. B. carbides, borides, nitrides, the metals of the IV. Main or subgroup of Periodic system, such as titanium carbide, silicon carbide or the like. Is made. 3. pen according to claim 1 or 2, characterized in that the material conductive salts of refractory precious metals, preferably iridium carbide, rhodium carbide or ruthenium carbide. 4. pen according to claim 1, characterized in that that the material of the pen small amounts of base metals such. B. Nickel, Chromium, copper, cobalt, indium, cadmium, beryllium or the like are added. 5. pen according to claim 1, characterized in that the material of the pen small amounts of noble metals, for. B. gold, palladium, platinum, are added. Documents considered: German Patent No. 1116 418.