1. The parallel port of the printing device is damaged or the data line problem
When the parallel port of the printing device is damaged or the data cable problem, you can replace the data cable to see if the printer can be used normally, but if it still cannot be solved, you can only contact the local printer repair center to solve it.
2. Error in printing program
In the event of a print program error, all print commands should be deleted immediately. Then turn off the printer power, unplug the data cable, restart the computer, and then reconnect the power and data cables. This can temporarily solve the problem of garbled printing, but if the problem of garbled printing occurs frequently, you still need to contact the repair center to repair or replace the printer.