How do you calibrate printer so it prints a perfect square?

Answer 1

That depends on the printer and the software. You have to scale it properly with the software, and the printers "encoder" and "mechanics" must be in good condition. Some Printers use an encoder strip that can get ink contamination and it will mess up the position, or if its a rotary encoder, it can go bad, or be loose on the shaft, or the stepper motor might be worn, or on some printers, a servo motor is used, and a servo calibration may be in order. Sometimes changing a worn belt or worn gear can restore sizing accuracy. Sometimes there is slop in the gear(s), sometimes the belt is loose. Most belts have fibers inside the belt, and when the belt gets old, those fibers break, and the belt acts somewhat like a rubber band, stretching out of position as the head is positioning. Any kind of mechanical slop can cause problems with sizing accuracy.