Epson Printer Paper Jam After Rear Assembly Repair: Nozzle Check Works, But Rear Feed and Main Tray Fail

Question:
After removing an obstruction wrapped around the half-moon roller in the rear assembly, I had to take the printer apart several levels deep to clear it and then reassemble everything. The printer now powers on normally, and aside from initially installing one ribbon cable backward, there are no startup errors. It can perform a nozzle check and pull paper from the front, but when printing from the rear feed, the paper does not track through properly and triggers a paper jam error. When printing from the main tray, the paper also misfeeds. In many cases, the printer starts feeding the sheet, then backs it up toward the rear manual-feed housing, where it catches on the flaps in front of the rollers. There was also some ink on the timing wheel, and although most of it was cleaned off, there is concern that it may still be affecting printer operation.

Answer:

From your description, the most important clue is this: the printer can do a nozzle check, but it fails during regular printing from the rear feed and the main tray, often feeding the paper partway and then reversing it back into the rear path until it catches and reports a paper jam. That pattern usually means the printer is not simply dealing with a random jam. Instead, it suggests that something in the paper feed path, sensor system, or gear timing is out of position after reassembly.

The first thing I would verify is that the upper frame gears and rear paper-feed mechanism were put back exactly in sync. Since you had to do a deep teardown to reach the half-moon roller, even one gear being off by a tooth can cause the feed rollers to start correctly and then lose synchronization once the paper advances farther into the path. That can make the printer think the paper is not where it expects it to be, which can trigger a paper jam condition even though the real issue is timing rather than a physical blockage. Please compare your assembly carefully against this video on the upper frame and gear installation: upper frame gear installation video [https://www.youtube.com/watch?v=4KTIj8zpnyo&feature=youtu.be].

Because the printer can still perform a nozzle check, the carriage system and at least part of the feed system are still functional. However, nozzle checks usually use a simpler and shorter paper path behavior than a full print job. During regular prints, the printer relies much more heavily on paper position monitoring, and that is why a faulty or misaligned PW sensor becomes a strong suspect. The PW sensor is the paper-width/paper-presence detection system, and if it does not read the sheet correctly, the printer may begin feeding, then reverse the sheet or stop and declare a paper jam because it thinks the paper is skewed, missing, or out of position. Based on the way your paper starts forward and then backs up, the PW sensor is one of the first things I would inspect. This video may help with that area: PW sensor solution video [https://www.youtube.com/watch?v=uG_p-1HiyHo].

Another likely possibility is that the PF gear or change gear is out of sync or worn. In Epson-style paper feed systems, those gears coordinate how the printer switches between feed states and how the rollers advance the paper. If one of them is slightly mispositioned during reassembly, the sheet may feed halfway, hesitate, and then get pulled backward or redirected incorrectly. That matches your report that the paper ends up backing into the rear housing and getting caught in the flaps near the rollers. If the printer retrieves the paper backward, I usually lean more toward a sensor-related problem, especially the PW sensor. If it simply fails to continue forward without retrieving, then I become more suspicious of the change gear or PF gear being out of time or mechanically damaged.

The fact that the problem happens from both the rear feed and the main tray is also significant. That usually means the issue is not limited to one paper source. If only the rear feed failed, I would focus mainly on the rear assembly. But since both sources eventually misroute or jam, the fault is probably somewhere in the shared downstream paper path, or in a sensor or gear system that controls both feed routes after the paper leaves the pickup stage.

Regarding the timing wheel, yes, ink contamination there can absolutely cause trouble, but it usually affects paper feed tracking accuracy rather than causing a simple pickup failure. If by "timing wheel" you mean the encoder-related wheel or disk used to monitor motion, leftover ink or smear on that surface can lead to incorrect motion readings. When the printer gets incorrect position feedback, it may stop feeding at the wrong time or misjudge where the paper should be, and that can contribute to a paper jam error. If any residue remains, clean it very carefully with a lint-free swab and an appropriate cleaner, being gentle so you do not scratch the markings. Even a small smear can sometimes confuse the reading.

I would also recheck the following during inspection:

• Make sure all ribbon cables are fully seated, straight, and inserted in the correct orientation. Since one cable was already found backward, it is worth rechecking every cable in the area you serviced. A partially seated sensor cable can allow the printer to power up normally while still causing paper-path detection problems.

• Inspect the rear paper path flaps and guide pieces to make sure none were installed slightly above or below their intended position. If one flap sits incorrectly, the paper can catch exactly where you described.

• Rotate the gears by hand and watch whether the rollers and guides move smoothly through a full cycle. Look for hesitation, slipping, or a position where a guide closes too early.

• Check for any small spring, clip, or guide tab that may have been displaced during teardown. These can be easy to miss, but they often affect paper routing.

• Look carefully for residual scraps of paper, fibers, adhesive, or debris near the half-moon roller, PW sensor area, and rear manual-feed housing.

As for the error codes, based on your description, the printer is mainly reporting a paper jam error rather than a numbered electronic fault code. Since you also mentioned that after correcting the reversed ribbon cable the printer powers on without startup faults, that is actually helpful: it suggests the core electronics are alive, and the problem is more likely in the mechanical feed path, sensor alignment, or gear timing rather than a hard board failure.

In practical terms, I would troubleshoot in this order:

1. Recheck the upper frame and all feed gears against the reassembly video.

2. Inspect and clean the PW sensor area.

3. Clean the timing wheel/encoder-related wheel again if any ink remains.

4. Verify every ribbon cable in the repaired area.

5. Inspect the rear guide flaps, manual-feed entrance, and shared paper path for anything slightly out of position.

6. If all of that looks correct, then suspect a change gear or PF gear synchronization issue.

Printer problems like this can be complicated because they are so hands-on and mechanical in nature. For that reason, we are not able to provide remote troubleshooting, repair suggestions, or one-on-one support for printer repair work. We do offer an in-person inspection and repair option through our local diagnostic service center, printer repair service [https://bchtechnologies.com/printer-repair-service]. Because demand is high, repairs are handled on a first-come, first-served basis, and it may take a few weeks before we are able to accept a drop-off. We can work on either an entire printer or a specific part, and the service page explains how to proceed. That said, we understand our pricing may not be the lowest, so we strongly encourage self-help research first. A great starting point is YouTube, including our channel homepage at BCH Technologies YouTube channel [https://youtube.com/@bchtechnologies]. You can use the search icon next to "About" on the right side of the menu bar to look for videos on the exact issue. We receive many messages every day asking whether we have already covered a specific topic, and after years of making videos, the fastest way to locate a relevant one is usually YouTube's own search. It may also suggest helpful videos from other creators.

Thank you again for reaching out and for supporting BCH Technologies. We truly appreciate your patience, your detailed explanation of the issue, and your continued engagement with our content.