Jagged lines can be caused by two things, either the printer resolution, or the file resolution.
If it is the printer resolution that would be up to the operator of the printer to fix. Graphics that are printed for close viewing should be printed at now less than 720 DPI.
The other possibility is that the files are crated in a raster based program and the resolution is set below 300 DPI. Text should always be done in a vector program, this gives very crisp sharp lines.
There is some great information on raster vs vector graphics here.
http://ctmexhibits.com/info/vectorvsraster.html