The Epson EcoTank ET-3700 is a reliable all-in-one supertank printer, but like any printer with a rear-feed paper path and internal duplexing mechanism, it can develop false or genuine paper jam errors. When your display shows error code E-01, a blinking paper light, or the message "Paper jam," printing stops completely. This guide walks you through proper diagnosis and resolution—whether there's actual paper stuck inside or the sensors simply need resetting.
Identifying the Real Cause
Before diving into printer repair procedures, it's important to distinguish between a physical jam and a sensor error. The ET-3700 uses multiple paper detection sensors along its U-shaped paper path: at the rear feed slot, inside the duplex unit, near the print head carriage, and at the front output tray. Dust, small torn fragments, or even displaced ink tubes can trigger a false Epson EcoTank ET-3700 paper jam error. Start troubleshooting by noting exactly when the error occurs—during single-sided printing, duplex (double-sided) printing, or immediately upon startup.
1
Power Down and Prepare the Printer: Turn off the ET-3700 using the power button and unplug the power cord from the rear. Wait 60 seconds for capacitors to discharge and sensors to reset. Remove all paper from the rear feed tray and output tray. Open the scanner unit completely and secure it in the upright position using the support arm—this exposes the print head area and internal paper path.
2
Clear the Rear Feed Path: The ET-3700 pulls paper from the rear upward into the mechanism. Remove the rear paper support extension completely. Shine a flashlight into the feed slot and look for crumpled paper, labels that detached from sheets, or foreign objects like paper clips. If you see jammed material, grip it firmly with both hands and pull slowly straight toward the rear—never pull upward or toward the front, which can tear paper and leave fragments on the pickup rollers.
3
Access and Clear the Internal Duplex Area: Paper jams frequently occur where the sheet reverses for duplex printing. With the scanner unit still raised, locate the white plastic duplex cover on the printer's left side interior. Press the release tab and swing this cover open. Check for paper wrapped around the duplex rollers or caught at the bend point. Remove any material carefully, then rotate the duplex rollers by hand to ensure they move freely—stiffness indicates debris you may have missed.
4
Inspect the Print Head Carriage Zone: The ET-3700's print head moves across a stainless steel guide rod, and paper can crumple in this area if the rear feed guides were misaligned. With power still off, manually slide the print head carriage to the center if it isn't already. Check for torn paper fragments, excessive ink buildup, or any obstruction on the encoder strip—the thin clear plastic strip running horizontally behind the carriage. Clean the encoder strip gently with a lint-free cloth slightly dampened with distilled water; ink or dust here can confuse the carriage position sensor and contribute to false jam readings.
5
Reset Paper Sensors and Power Cycle: After confirming all paper is removed and covers are reseated, perform a hard reset. Close all covers firmly until they click. Plug the power cord directly into a wall outlet (avoid surge protectors for this test, as some can cause voltage irregularities). Hold the power button for 10 seconds while unplugged, then release. Plug in and power on. If the Epson EcoTank ET-3700 paper jam error persists with no visible jam, the issue likely involves a stuck sensor flag or firmware glitch requiring deeper intervention.
6
Clean Feed Rollers and Verify Paper Loading: Persistent jams often stem from worn or contaminated pickup rollers. With the printer on, press and hold the maintenance button (the one with the ink droplet icon) for 3 seconds to enter roller cleaning mode. For manual cleaning: power off, moisten a lint-free cloth with water, and gently scrub the gray rubber pickup rollers visible through the rear feed slot while rotating them. When reloading paper, fan the stack first, align edges squarely, and ensure the paper size guides in the rear tray are snug against the edges—loose guides cause skewed feeding that triggers jams.
⚠️ Important: Never use tools like tweezers, screwdrivers, or vacuum hoses inside the ET-3700. The duplex sensors and ink tube routing are easily damaged. If you cannot see and manually reach jammed paper, forcing removal may destroy the paper path sensors, turning a simple fix printer situation into a costly hardware replacement. If paper tears during removal and fragments remain lodged, stop and contact professional printer support.
When Professional Help Is Needed
If you've completed all troubleshooting steps and the error continues, several hardware issues could be at play. The ET-3700's paper eject sensor (a small micro-switch with a plastic flag) can break off after repeated jams. The pickup roller assembly may be worn smooth after heavy use. In rare cases, the main board's sensor input circuits fail, causing constant false jam signals regardless of actual paper status. These problems require disassembly and component replacement that goes beyond typical user-level tech support. Professional Epson printer repair technicians have access to service manuals, diagnostic modes, and genuine replacement parts including the specific sensor assemblies for this model.
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Why does my ET-3700 show a paper jam error when there's no paper inside?
This is typically a false sensor reading caused by tiny torn fragments you missed, dust on the encoder strip, or a stuck sensor flag. Complete the hard reset procedure in Step 5 and inspect the duplex cover area carefully—many "invisible" jams hide where the paper path bends.
Can I continue printing if I bypass the error by turning the printer off and on?
Repeated power cycling without resolving the underlying cause risks damaging the print head or paper path mechanisms. If the Epson EcoTank ET-3700 paper jam error returns consistently, there's a genuine problem requiring proper troubleshooting or professional printer repair.
Does using third-party paper cause more jams in the ET-3700?
Yes. Paper heavier than 24 lb (90 gsm), highly textured stock, or paper with pre-punched holes can misfeed in the ET-3700's rear path. Always use plain copy paper within the specified 20-24 lb range, store paper in a dry environment, and load only enough for your immediate printing needs to prevent moisture absorption that causes sticking.