give me four ways regarding typewriter?

Question

four ways that a typewriter can be identify

Answer 1

Do you mean a real typewriter with separate molded letters for each character?
Do you mean identify which typewriter printed a sample from the printed sample?
If so, then
1. A letter may print at a slight angle to the others
2. A letter may print slightly above or below the others.
3. A letter may have a flawed casting so part of the letter is narrower or missing.
4. A letter may be tilted so the top or bottom is lighter than the other end.
5. In the short term (without cleaning) the letters with holes in them, like a, o, e, etc., may fill in the hole with dirt and thus print a more or less dark center instead of a clean outline.
6. A worn or shrunken roller may skew the paper slightly so the lines at the bottom of a page are not parallel to those at the top.
7. A worn or shrunken roller may allow the paper to slip, so that lines, especially those at the bottom are further appart or closer together than the rest.
8. A roller may have been typed on or otherwise gotten dirty so the back of the paper shows regular patterns of dirty markings.
9. Either the typist or the mechanism may have applied too much force to that certain characters, like period and comma, make too deep an impression or cut the paper, which can be seen from behind. May also happen with an old thin ribbon and increasing the force to get a clear image.
10. A worn roller may cause lines to have ripples, that is to rise and fall instead of being straight across the paper, most obvious in a line of dashes ---------------, but also shows in letter patterns.