Once again, legal questions vary from country to country and you do not state where you are.
In the USA a signature is generally taken as any mark placed upon the document with the intention of being a signature. It does not even need to be made by the person that the signature belongs to, it can be made by someone else as long as the responsible person affirms it as his signature. This is useful in cases where someone breaks both his wrists for example but still needs to endorse his paycheck.
My advise to you is to simply do what you have planned. If for some reason someone asks you for a "real" paper document rather than a FAXed or electronic one, you can always sign with a pen to satisfy those rare cases.
In the US and most developed nations, the answer is yes an automated signature is considered legally valid. (Both electronic and mechanical) See:
Mechanical Signatures From a practical point of view, the vast majority of all paychecks in the US are autosigned. There is no one at General Electric signing each paycheck. And there is no one at the IRS signing your tax refund or Social Security Check. Most computer printed documents that are autosigned use a signature font. The reason for the use of a font is that the vast majority of computer software support the use of fonts (not graphic images), and fonts are scalable- you can size the signture to fit the document.
My firm has been converting signatures into fonts for over 22 years. See:
You can sign with Digital Signature. Adobe PDF has tools in which you can add your scanned of your physical signature along with the digital signature. I personally used such signature. Personally feel that is safe as no changes can be made.