Epson ET-8550 Lower Tray Paper Jam, Creased Paper, Multiple Sheet Feeding, and Paper Reversing After Setup

Question:
I set up a brand-new Epson ET-8550 and transferred over some parts, including the CISS tanks. The unit primed correctly, but when I ran a print head check using 8.5" x 11" paper from the lower tray, the paper jammed and developed a crease down the middle. I checked for shipping tape and packing blocks but did not find anything left behind. On another attempt, it printed the first sheet, then seemed to bind, pulled the sheet backward, and ejected it. After that, the printer started pushing out four or five blank sheets very quickly from the lower tray. I also noticed clacking noises from the top feeder area. Since I already had another ET-8550 for several months, I skipped installing the new printer driver on my laptop and only completed the printer's onboard setup before running the nozzle check. I am wondering whether this could be caused by a sensor issue or by not installing the new driver.

Answer:

Based on your description, this does not sound like a driver problem as the primary cause. Since the printer is already attempting mechanical paper feeding and performing a nozzle check sequence, the missing driver on the laptop would normally not cause paper to crease, reverse direction, or eject several blank sheets. Those symptoms point much more strongly to a paper feed mechanism issue, a paper width detection issue, or a sensor/mechanical timing problem.

One important possibility is the PW sensor (paper width sensor). When this sensor does not read correctly, the printer can behave in very odd ways. A common symptom is that the print starts, the carriage moves as if printing normally, then the printer decides the paper position is wrong, pulls the page backward, or ejects extra sheets. In some cases, it may feed multiple sheets rapidly because the machine is not correctly confirming paper position or paper width during the feed cycle. So yes, a sensor issue is definitely possible, and the PW sensor is high on the list based on the behavior you described.

Another strong possibility is the lower cassette pickup mechanism itself. Since the problem is happening specifically from the lower tray, and you are seeing paper crease in the center, retreat backward, and then multiple sheets feeding out, you should inspect the pickup and release system in the lower feed path. In the ET-8550 exploded parts reference, pay close attention to 501 Pick Up Assembly, 538 Pick Up Drive Shaft, and 548 Pick Up Release Lever Shaft in the ET-8550 exploded parts diagram repair reference guide (https://bchtechnologies.com/products/et-8550-et8550-exploded-parts-diagram-repair-reference-guide-annotated-edition?_pos=2&_sid=629ec696b&_ss=r).

When you insert the tray, 501 should lower into position properly. If it does not engage correctly, the printer may fail to separate and pick paper correctly. That can lead to skewed feeding, several sheets being pulled through, or a jam that creases the paper in the middle. If 501 is not lowering as it should, then the next part to inspect is 506 Frame Bank, because that assembly influences the pickup geometry and alignment.

The fact that the paper is creasing in the middle is especially useful diagnostically. A center crease often means the sheet is encountering resistance somewhere in the feed path while the rollers are still pushing. On this model, that means you should also inspect the 913 Rear Frame and the LD Shaft area. If something in that section is slightly out of position, binding, or not seated correctly, the paper can buckle instead of moving forward smoothly. Once the paper buckles, the printer may interpret the feed incorrectly, stop, reverse, or eject the sheet.

A very good isolation test is to feed a sheet from the rear tray instead of the lower cassette. If the rear tray feeds correctly and consistently, that strongly suggests the printhead and main paper transport path are probably fine, and the problem is more likely limited to the lower tray pickup system, tray alignment, or lower-path paper sensing. If the rear tray also shows the same retreating or skewing behavior, then the issue becomes more likely to involve a shared sensor or downstream transport problem rather than only the cassette pickup parts.

The clacking noise you mentioned from the top feeder area is also important. That type of sound often points to a gear timing issue, a pickup cam not returning properly, or a lever/shaft not engaging the way it should. Even on a new machine, this can happen if a mechanism was jarred during shipping, if a linkage is slightly out of place, or if a transferred part affected alignment. Because you moved over some parts and CISS components, I would also double-check that no transferred component, tubing, or bracket is interfering with the paper path, sensor flag movement, or tray lift action. Sometimes a small interference point can create a chain of symptoms that looks much larger than it really is.

As for the printer ejecting four or five sheets quickly, that usually suggests the machine is repeatedly trying to recover from a failed feed state. In practical terms, that means it may be failing to confirm paper registration properly, or it may be incorrectly detecting the presence, size, or position of the page. Again, this points more toward the pickup/feed system or the PW sensor rather than software.

Regarding error codes: you did not mention a specific paper jam code in your message, so I cannot confirm an exact numeric code from the symptoms alone. On Epson machines, these kinds of issues may show up as a paper jam message, paper feed error, or paper not loaded correctly type warning on the printer display, even when the real cause is mechanical timing or sensor-related. If your screen shows a specific code during the jam sequence, that code would help narrow down whether the machine is losing track of the paper at pickup, registration, or transport. Still, even without a code, the pattern you described already points to the lower cassette feed system and paper sensing as the most likely areas.

Here is the order I would use for checking it:

First, try a page from the rear tray. If rear feeding works normally, focus on the lower tray system.
Second, inspect whether 501 Pick Up Assembly lowers correctly when the tray is inserted.
Third, inspect 538 Pick Up Drive Shaft, 548 Pick Up Release Lever Shaft, and 506 Frame Bank for improper movement, misalignment, or anything not engaging smoothly.
Fourth, inspect 913 Rear Frame and the LD Shaft area for anything that could cause the paper to buckle and crease.
Fifth, look carefully at the PW sensor path and sensor flag movement to make sure nothing is blocked, bent, or stuck.
Finally, verify that no transferred CISS-related part or tubing is interfering with any feed mechanism.

I would still recommend installing the proper driver later for completeness, but based on what you described, I would treat that as a secondary housekeeping step, not the root fix. Driver installation is good practice, but it would not normally create physical paper creasing, backward paper movement, or repeated blank-sheet ejection during a basic onboard nozzle check.

Printer issues like this can be tricky because they are so hands-on and mechanical in nature. For that reason, we are not able to provide remote repair troubleshooting or step-by-step repair support beyond general guidance. We do offer an in-person evaluation and repair option through our local printer repair service (https://bchtechnologies.com/printer-repair-service). Because demand is high, we handle repairs on a first-come, first-served basis, and it may take a few weeks before we are able to accept a drop-off. Our service structure allows for either whole-printer repair or work on specific assemblies, with clear instructions on how to proceed. That said, we understand our rates may not be the lowest, so we strongly encourage self-help research whenever possible. A great place to start is YouTube, especially our BCH Technologies YouTube homepage (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 your exact topic. I receive many questions every day asking whether we have a video on a specific repair, and after many years of making videos, YouTube's search function is usually the fastest and most reliable way to find the right one. It may also suggest useful videos from other channels that can help.

Thank you again for reaching out and for your continued support. We truly appreciate your trust, your patience, and your support of BCH Technologies.