What Is the Encoder Strip?
The encoder strip is a thin, clear plastic strip that runs from left to right inside your printer, usually above where the print head moves. It has fine black lines printed on it. As the print head moves, a sensor reads these lines to know exactly where the print head is positioned. When the strip gets dirty or damaged, the sensor can't read it properly, and error 5100 appears.
Why This Happens:
Over time, dust, ink mist, and fingerprint oils build up on the encoder strip. Even a small amount of dirt can block the sensor from reading the position marks correctly. The printer then doesn't know where the print head is and stops with error 5100 to prevent a crash.
Fix #1: Clean the Encoder Strip
Clean the encoder strip using isopropyl alcohol (rubbing alcohol) or window cleaner and a lint-free cloth. This fixes error 5100 in most cases.
What You'll Need:
- Isopropyl alcohol (70% or higher) or window cleaner
- Lint-free cloth, microfiber cloth, or coffee filter
- Good lighting or a flashlight
Steps:
- 1. Turn off your Canon printer and unplug it
- 2. Open the printer cover as if you were changing ink
- 3. Look for a clear plastic strip running from left to right above the print head path. It will have fine black lines on it
- 4. Lightly dampen your cloth with isopropyl alcohol or window cleaner (don't soak it)
- 5. Gently wipe both sides of the encoder strip from one end to the other
- 6. Don't pull, stretch, or bend the strip
- 7. Make sure you remove all dust, ink residue, and smudges
- 8. Let it air dry for 2 to 3 minutes
- 9. Close the cover, plug in the printer, and turn it on
Be Careful:
Don't touch the encoder strip with your bare fingers after cleaning it. The oils from your skin will leave smudges and cause the same problem again. Also, don't use paper towels, they can scratch the strip or leave fibers behind.
Fix #2: Check for Obstructions
Check for anything physically blocking the print head from moving smoothly. Sometimes error 5100 is caused by obstructions, not a dirty encoder strip.
Steps:
- 1. Unplug the printer
- 2. Open the cover and look carefully at the entire path the print head travels
- 3. Check for any paper scraps, torn labels, or debris
- 4. Remove anything you find
- 5. Gently move the print head left and right by hand (with the printer unplugged). It should move smoothly with no catching or resistance
- 6. If you feel resistance, look more carefully for what's blocking it
Fix #3: Power Reset the Printer
Perform a complete power reset after cleaning the encoder strip or removing obstructions to clear the error from memory.
Steps:
- 1. Turn off the printer
- 2. Unplug it from the wall outlet
- 3. Wait 60 seconds
- 4. Plug it back in
- 5. Turn it on and let it complete its startup
Fix #4: Replace a Damaged Encoder Strip
Replace the encoder strip if cleaning doesn't work and it looks torn, cracked, or heavily damaged.
Replacement encoder strips can be ordered online by searching for your Canon printer model number plus "encoder strip" or "5100 encoder strip replacement." They're usually inexpensive (under $10 to $15).
Installation varies by model but generally involves removing the old strip from its holders and sliding the new one into place. Look for YouTube videos for your specific Canon model to see the process.
Common Mistakes to Avoid
- ✗Don't use too much liquid: The cloth should be barely damp, not dripping wet. Too much liquid can damage the printer's electronics.
- ✗Don't stretch or pull the encoder strip: It's delicate and can tear or come out of its holders if you're not gentle.
- ✗Don't skip both sides: The encoder strip has markings on both sides (or dust can be on both sides). Clean both sides for best results.
How to Prevent This Problem
- ✓Keep your printer covered: Dust is the main cause of dirty encoder strips. Cover your printer when not in use.
- ✓Clean the encoder strip regularly: Clean it every 6 months to a year as preventive maintenance.
- ✓Don't touch the strip: When changing ink or working inside the printer, avoid touching the encoder strip with your fingers.
- ✓Print regularly: Printers that sit unused for months accumulate more dust.