If paper jams are still present, you can try using special paper designed to clean the rollers, paper supports and other objects in the paper path.
Ink problems are often when printing vertical lines and blurring on paper. The reason is often because the print head is dirty or the ink in a laser printer is running low.
For inkjet printers, the print head needs to be cleaned. Utility applications that come with printers often have cleaning options. There are usually two types of mild cleaning and deep cleaning. You should start with a lower level because this cleaning process often takes a lot of ink. If that doesn't work, move on to a higher level.
For laser printers, the reason may be that the ink is low, indicating that it is time to replace the ink. If you're printing badly and don't have a toner cartridge to replace, you can take advantage of it by removing the toner from the printer and slowly shaking the cartridge, making sure the cartridge is closed when you do this. If you're lucky, you'll have enough level to print when waiting to replace another cartridge.