UV Printer Ink Supply Problem Captop Replacement Method ARTJET 2025

• UV printers that use a damper and Captop do not specify an exact Captop replacement interval.
• In practice, replacement is considered when inkload (pumping) problems occur.

Causes of air bubbles appearing together with ink during pumping:

• The ink line is loosely connected to the damper at the print head channel, allowing air to enter through the gap
• The damper is not fully inserted into the print head channel, allowing air to enter
• A small amount of air is entering through the ink tube fitting
• The damper itself has burst, allowing air to enter
• The print head underside and Captop are misaligned, breaking the seal
• The Captop lower tube connection has loosened, allowing air to enter
• A non-dedicated tube is being used for the Captop lower connection, preventing a proper seal
• The peristaltic pump yellow tube has worn through and air is entering through the tear

• The Captop and print head are completely misaligned
• The peristaltic pump yellow tube has shrunk severely, preventing pumping entirely
• Part of the ink line has torn from wear, leaving the line empty of ink
• A section of the ink line is kinked and blocking ink flow

• If any of the above situations occur, replace the Captop first before checking anything else — this is the fastest way to resolve inkload problems.
• Inspecting everything else before replacing the Captop wastes valuable time narrowing down the cause.
• Eliminating the Captop as a variable first is the most efficient troubleshooting approach.

Problems that can only be resolved by replacing the Captop:

• Residual ink inside the Captop has hardened, preventing inkload (pumping)
• Inkload and cleaning both work fine, but nozzles drop out during printing — in this case, degraded residual ink inside the Captop is contaminating the ink on the head surface, and Captop replacement is the only solution

• Never loosen the bolts visible in the photo above.
• Doing so will shift the carefully set alignment between the print head underside and the Captop — inkload may fail even after the Captop is replaced.
• Loosening those bolts will not allow you to replace the Captop anyway.
• The Captop can be removed and reinstalled separately without loosening the bolts at all.

• With the printer powered on, press the button to move the head carriage to the left (toward the flatbed) to create working space.
• Place tissue paper under the yellow tube to prevent ink contamination.
• Disconnect the Captop lower tube from the yellow tube.
• Remove the Captop from the capping station and keep the spring somewhere safe so it doesn’t get lost.
• Use nippers to cut the tube connected to the Captop lower port, separating the Captop from the tube.
• Since the Captop lower tube will be reused, cut as close to the Captop lower connection point as possible to preserve maximum tube length.
• Use nippers to cleanly cut off the two unnecessary plastic posts on the new Captop.

• Now connect the tube to the Captop lower port.
• It will be very tight and difficult to insert — this is normal. You need to push it in firmly. Once connected, it should not pull out even when you try by hand.
• Attach the spring, then reassemble the Captop into the capping station.
• Reconnect the Captop lower tube to the yellow tube.
• Using any random tube will always cause problems. Always use the dedicated Captop lower tube.

• If this is your first time, removing and reinstalling the Captop may not be easy. The video below will help you complete the process smoothly.
• Watch the Captop Replacement Video