Diagnosis
A "phantom" paper jam on the Canon PIXMA TR4720 usually occurs when a tiny fragment of paper—often a torn corner or a scrap from a previous jam—is obstructing a photo-interrupter sensor. Even if the main paper path looks clear, a shred as small as a confetti piece can keep the sensor tripped, preventing the printer from resetting its error state.
How to Fix It
Follow these steps to clear the hidden obstruction:
- Power off the printer and unplug the power cord to prevent electrical shorts and motor damage.
- Open the rear cover (the duplexing unit) and inspect the rollers. Use a bright flashlight to look for small white scraps lodged in the gears or rollers.
- Open the scanning unit/cover to access the print head carriage. Gently slide the carriage to the center if it isn't already there.
- Inspect the far left and right ends of the carriage path. Small pieces of paper often accumulate in the "parking" area where the ink cartridges rest.
- Use plastic tweezers or a can of compressed air to remove any debris. Avoid using metal tools, as scratching the encoder strip (the clear plastic band) will cause alignment errors.
- Close all covers and plug the unit back in.
If That Didn't Work
If the error persists, the jam may be located in the Auto Document Feeder (ADF). Open the ADF cover and check the small rubber rollers for debris. Additionally, perform a "hard reset" by unplugging the printer and holding the power button for 15 seconds to discharge remaining electricity, then restarting. If the error remains, the sensor arm itself may be stuck in the "down" position; gently blow compressed air around the sensor flags in the paper path to flick them back into place.
Heads Up
Never force the print head carriage if it feels locked; you may snap the timing belt. Always ensure the printer is completely powered down before reaching deep into the internal mechanisms to avoid pinching your fingers in the motorized gears.