Etydhv

I was taught in school many years ago (in the 1960s) that there is no such thing as a proper verb. Example: I used the Xerox machine and xeroxed the document.
Or: I will use my bottle of Windex to windex the mirror.

Is this corrector not?

Your examples illustrate metonymy

: a figure of speech consisting of the use of the name of one thing for that of another of which it is an attribute or with which it is associated.
(https://www.merriam-webster.com/dictionary/metonymy)

Another example of the metonymy is
boycott.

According to Etymologyonline:
1880, noun and verb,
"to combine in refusing to have dealings with, and preventing or discouraging others from doing so, as punishment for political or other differences."

From Irish Land League ostracism of Capt. Charles C. Boycott (1832-1897).

The Cambridge Dictionary gives the capitalised verb:

Google

On the basis that dictionaries are authorities on whether a word is a word or not—at least for pedants—English does indeed appear to have proper verbs, so to speak.

The word "xeroxed" is an example of conversion. Conversion means the change of a word class without a change in form. It is very productive in English. For example, I can use the noun bottle and turn it into a verb he bottled the milk, or the adjective green and turn it into a noun we went out into the green, an ungradable adjective like English and turn it into a gradable adjective, he is very English, etc. In your case, you took a proper noun, Xerox, and turned it into a verb, to xerox. That does not make the resulting word a "proper verb", which is not even a recognized category in linguistics. It makes it a verb converted from a proper noun.