Usually, it usually happens when the printer's driver may get outdated, corrupt, and become incompatible with the system. But, its strange if your issue is not resolved even after reinstalling and updating the driver.
Hello HomerSimpson,
I searched our knowledge base and found and article for gibberish prints. If you are still having issues after trying these steps, I suggest that you call into our support department for assistance @ 1-800-835-6100.
My C235 started printing random, garbage characters on many, many pages. This happens when printing a pdf, a png, or the test page from the driver. The configuration reports print fine from the printer's touchscreen menu.
I reinstalled the recommended print driver, and updated to the latest firmware, all without success. What's next?