my canon ts3520 printer keeps showing 'error 5100' and won't print anything, just makes a grinding noise.

Diagnosis

Error 5100 on the Canon PIXMA TS3520 is a critical carriage error. This occurs when the print head carriage—the component that holds the ink cartridges—cannot move freely across the width of the printer. The grinding noise you hear is the stepper motor attempting to force the carriage forward while it is physically obstructed, which can eventually strip the plastic gears if not addressed immediately. This failure is typically caused by one of three things: a small piece of torn paper lodged in the far left or right corners of the carriage path, a buildup of thickened ink residue on the encoder strip (the thin, clear plastic ribbon behind the carriage), or a foreign object like a paperclip or staple that has fallen into the chassis. You can confirm this by opening the scanning unit/cover; if the carriage is skewed or stuck at an extreme angle rather than centered, you have a mechanical obstruction.

How to Fix It

Follow these precise steps to clear the obstruction and reset the carriage system:

1. Power down the printer completely. Press the Power button, then physically unplug the AC power cord from the wall outlet to discharge any remaining electricity in the capacitors.
2. Lift the scanning unit/cover to access the interior. Use a high-intensity LED flashlight to inspect the far left and right "parking" stations. Look for tiny scraps of paper, often no larger than a fingernail, that may be wedged in the guide rail.
3. Check the encoder strip. This is the translucent plastic strip running horizontally across the printer. If you see smears of ink or grease on this strip, the printer "loses its place," triggering Error 5100. Gently wipe the strip with a dry, lint-free microfiber cloth. Do not use rubbing alcohol, as it can erase the microscopic timing marks on the strip.
4. Gently grasp the print head carriage. With the power off, slowly slide it from one side to the other. If you feel resistance, do not force it; look for the specific point of friction. Ensure the ink cartridges (PG-275 and CL-276) are snapped firmly into place and aren't protruding downward, which could cause them to snag on the paper feed rollers.
5. Clear any debris from the paper feed path using a pair of tweezers. Ensure no paper is curled underneath the carriage rail.
6. Close the cover, plug the power cord back in, and turn the device on. The printer will perform a calibration cycle; wait for it to finish completely before sending a test page.

If That Didn't Work

• Perform a Hard Power Reset. While the printer is on, unplug the power cord from the back of the machine. Wait exactly 60 seconds. While unplugged, hold the Power button down for 15 seconds to drain the internal logic board. Plug it back in and restart. This clears the volatile memory that may be "remembering" the error state.
• Check for "Paper Ghosting." Sometimes a page is stuck in the rear tray but hasn't reached the carriage yet. Open the rear tray and use a flashlight to see if a sheet is partially fed. If so, pull it out slowly in the direction of the paper path to avoid tearing.
• Inspect the Carriage Belt. Look at the black rubber belt that moves the carriage. If the belt has slipped off its pulley or has a visible tear/stretch, the carriage will move unevenly, triggering the 5100 code. If the belt is loose, the unit typically requires professional mechanical service as the tension springs are not user-serviceable.
• Update Firmware. If the hardware is clear but the error persists, connect the printer via USB to a PC and run the Canon update utility. Occasionally, sensor sensitivity thresholds are adjusted via firmware updates to prevent "false positive" carriage errors.

Heads Up

• Avoid using canned air (compressed air) inside the TS3520. The high pressure can push small debris deeper into the gear assembly or displace the encoder strip, making the problem worse.
• Never force the carriage to move if you feel a hard stop. Forcing the carriage can snap the plastic guide rails or strip the drive gear, which renders the printer unrepairable.
• Keep the printer covered when not in use. Dust and hair accumulation on the encoder strip are the leading causes of "phantom" 5100 errors in home environments.
• Only use genuine Canon ink or high-quality compatible cartridges. Leaking third-party cartridges can drip ink onto the carriage rail, creating a sticky residue that slows the motor and triggers the error.