Ink eraser

An ink eraser, just killer, even Tintentod, blotters or ink eraser pen is a pen with which you can make corrections with ( mostly blue ) ink written texts. There is usually an ink eraser pen of two parts. With the one end you can make the ink "invisible" with a felt pen on the other end then make the correction.

History

Even before 1900, industrially manufactured means for removing ink under the names Radierwasser and Tintentod were generally known and commercially available. The first copies of the commercial contained the active substance as a pressed pin ( similar to Rasierstiften ). How to use this dampened and removed the ink with it. Subsequent products, such as sold under the brand Pelikan since about 1930 displaced, consisting of two vials set containing the active substance as a solution. This includes the 1972 Come as a novelty on the market pen INK KILLER as a trademark of that company cruiser in Bonn. The identical model sales later than Pelikan ink tiger.

Operation

All common inks are organic dyes. You possess a chromophore, a moiety with "free" mobile electrons that can be excited by light of a certain wavelength ranges. The incident light is therefore absorbed in this wavelength range. The light of other wavelengths is reflected. Thus, the wavelength distribution is changed in the (partial) reflection whereby the reflected light is given a color. As a blue fountain pen ink especially triphenylmethane dyes are used as water blue.

Is the mobility of the coloring electron disturbed, the dye loses its color. In the case of triphenylmethane dyes is often sufficient to influence the central carbon atom, for example, with a nucleophile of.

Delete with sulfites

This disorder can be, for example, with sulfites. This overlap of OH - and HSO3 - to the central carbon atom of the dyes. For this purpose are, for example, sodium sulfite ( Na2SO3 ), sodium bisulfite ( NaHSO3 ) or potassium ( K2SO3 ). This principle corresponds to the production of acid fuchsin from fuchsin.

Delete with carbonates

Another, slightly less effective way is the fault with carbonates such as sodium carbonate ( Na2CO3) or sodium bicarbonate ( NaHCO3). Here also lie Oh at the central carbon atom.

Delete with thiosulfate and dithionites

In addition to some more complex substances recently come dithionite or thiosulfate (eg Na2S2O3 ) for ink eraser in question.

Practical Implementation

In practice, these reducing agents are ( just above the sodium carbonate) reinforced by other materials such as alcohol or soda.

Canceling the effect

The ink is not destroyed during the erasing operation, as described above, but invisible. The conversion back to a visible form or aldehydes can be accomplished with the steam for about 36 % hydrochloric acid. By heating, preferably with hot air, the quenching effect can be to a certain extent also canceled. The ink is after a long time (several years, eg in old exercise books ) partially visible again.

Magic pens and " invisible ink "

The same principle can be written with an ink eraser also secret messages that are visible when using a thick brush over a large area and not too intense ink is applied. There are around since the 70's special " magic pens", which have a thin writing tip and a very thick brush -like fiber tip, with the one usually also invisible ink is applied over a large area, the combined color reacts only with the " invisible ink ". However, the term "magic pen" partially used as a synonym for the ink eraser itself. As a home remedy for invisible inks and lemon or certain fruit juices or milk can be used. The writing is mostly visible when exposed to heat.