Why Does My Epson L1800 DTF Printer Start Printing Fast but Gradually Slow Down Without Any Error Lights?

Question

My Epson L1800 DTF printer starts printing at a good speed, and the print quality looks fine. However, after a while, the printing speed slows down noticeably. There are no warning lights or error messages. I've watched your videos but haven't seen anything specifically about a printer slowing down without showing errors. Can you help me understand what might be causing this?

Answer

Based on your description-good print quality, normal start speed, then gradual slowdown with no warning lights or error codes-one very likely cause is the CR (Carriage Return) motor losing torque during operation.

How the CR Motor Affects Print Speed

The CR motor is responsible for moving the printhead carriage back and forth across the page. The printer's mainboard constantly monitors this movement using the CR encoder strip and sensor. If the carriage motor cannot keep up with the expected speed, the firmware does something subtle: it slows down the entire print process to allow the carriage to catch up. Because the system still sees movement within acceptable limits, no error code is triggered.

This is why you may notice the printer gradually becoming slower without seeing errors such as CR motor errors or carriage jams. The system is compensating rather than stopping the job.

Why This Happens More Often in DTF Conversions

Many L1800 printers used for DTF printing were originally designed as photo printers, not production machines. Their carriage motors were intended for intermittent use, not long continuous runs.

DTF printing typically involves longer and heavier workloads, which places more stress on the carriage motor. Over time, two main issues can occur.

1. Heat Buildup During Long Print Jobs

When you run extended print jobs, the CR motor heats up. As the temperature rises, the electrical resistance inside the motor coils increases.

Higher resistance means the motor draws current less efficiently, reducing its torque output. When this happens:

• The carriage movement becomes slightly weaker.

• The printer firmware compensates by slowing the print speed.

• You may see a gradual slowdown during long production runs.

If you print only a few sheets, you may never notice this issue. However, during larger batch jobs, the slowdown becomes more obvious.

2. Long-Term Magnet Weakening

Repeated overheating can cause demagnetization of the motor's internal magnets over time.

When the magnets lose strength, the motor permanently loses torque. This means the printer may run slower even when the motor is not currently overheating. In older or heavily used printers, this gradual decline in motor strength can make the slowdown more noticeable.

Signs That the CR Motor May Be the Cause

You may be dealing with a weakening carriage motor if you notice:

• The printer starts fast but slows down after a while

• No error codes appear

• Print quality remains normal

• The slowdown happens during long print runs

• The printer improves again after cooling down

Possible Solution: Upgrading the CR Motor

One potential solution is replacing the original carriage motor with a higher torque version designed for heavier workloads.

You can consider upgrading to this motor:
Industrial High Torque CR Motor Upgrade for Epson ET-8550 / L1800 / R1390 / 1390 DTF Printers
(https://bchtechnologies.com/products/industrial-high-torque-cr-motor-upgrade-for-epson-et-8550-l1800-r1390-1390-dtf-printers?_pos=1&_sid=26b8e0d4b&_ss=r)

This type of upgraded motor provides stronger torque and better thermal tolerance, which can help maintain consistent printing speed during long DTF production runs.

Other Factors Worth Checking

While the CR motor is the most common cause of this symptom, it's also worth checking:

• Carriage rail lubrication - A dry rail increases load on the motor.

• Belt tension - A worn or stretched carriage belt can reduce movement efficiency.

• Encoder strip cleanliness - Dirt on the strip can cause inaccurate carriage positioning feedback.

• Excess carriage weight - Some DTF conversions add tubing or dampers that increase drag.

Even small mechanical resistance can contribute to the printer slowing down as the motor heats up.

Addressing printer issues can be a complicated affair due to the hands-on nature of the problems. Therefore, we're not able to provide remote troubleshooting, suggestions, or direct repair support for printers. However, we do offer an in-person evaluation and repair service through our local diagnostic facility: BCH Printer Repair Service (https://bchtechnologies.com/printer-repair-service). Due to high demand, we operate on a first-come, first-served basis, and it may take a few weeks before we can accept a printer drop-off.

Our services are structured to repair either the entire printer or specific components, with clear instructions on how to proceed. That said, we recognize that our repair rates may not always be the most economical option. For that reason, we strongly encourage customers to explore self-help resources first. A great place to start is YouTube, including our channel homepage: BCH Technologies YouTube Channel (https://youtube.com/@bchtechnologies). Use the search icon located next to the "About" section on the right side of the channel menu to find videos related to your specific issue.

I receive dozens of questions every day asking whether we have a video on a certain topic. After producing videos for more than nine years, it's difficult to remember every single one. Using YouTube's search feature is often the fastest way to locate helpful tutorials. YouTube may also recommend additional videos from other creators that can guide you through similar repairs.

Thank you again for reaching out and for supporting BCH Technologies. We truly appreciate your engagement and hope this explanation helps you move closer to resolving the issue with your printer. If you continue experimenting with solutions, we wish you the best of luck getting your machine back to full speed.