It probably doesn't, my digital camera software when installed adds lot of files to the startup as does my Epson all in one. If I want to use them I click on them under program files I do not like having loads of programs running in the background as its not neccessary and slows things up.
Goto START. RUN and type MSCONFIG the last label has startup programs, find the ones for you printer and unclick the boxes and then restart the PC. If problems do appear, and they shouldn't you can always click them again by the same method. Only unclick the printer software as some of the other files are needed for windows to actually run.