Captop and head position _ Printer Cleaning Issues Part 5 ARTJET 2026

• When ink enters the Damper from the main ink bottle via the ink tube, it passes through the print head, flows to the captop, moves through the motor pump, and finally drains into the waste ink bottle.
• This article covers the Captop and Head Position section of the full ink supply problem series.
• This follows Part 1 Captop Lower Tube, Part 2 How to Replace the Captop, Part 3 Damper, and Part 4 Pump Motor and Yellow Tube.

• After checking all previous parts (Captop Lower Tube, Captop Replacement, Damper, Pump Motor), if pumping still fails, this article explains captop and head position as the next item to inspect.

The head and capping station are verified during the initial machine setup. If the head bottom and captop are not precisely aligned, cleaning or pumping will not work properly.

• If the capping station plate tilts heavily to one side, pumping may fail on specific heads even if the captop and head position appear correct.
• For example, color heads may pump fine while white heads on the tilted side fail to seal properly, preventing pumping.
• Even with a spring under the captop, if the carriage base plate tilts significantly, one side receives more force while the other receives less — the lower-force side will not seal.

A real field case:

• White channels 1 and 2 recovered immediately after cleaning, but channels 3–6 consistently failed to recover.
• Replacing the captop resolved the issue right away, but the same problem returned the next day (it worked only while the captop rubber blade was still firm).
• Inkload (pumping) itself was not failing, making the root cause hard to identify.
• The capping station was tilted, causing white channels 3–6 to fail to expel ink properly during pumping, preventing nozzle recovery.
• After more than a month of troubleshooting, leveling the capping station finally solved the problem.

The X-axis home position is where the head caps onto the captop when the printer is idle, and also the position used during cleaning and pumping. If this position is off, head protection, cleaning, and pumping will all be compromised.

• In software, click [Bi-Direction] → adjust [Origin springback(mm)] value
• Adding or subtracting 3 moves the position approximately 1mm (labeled in mm but does not correspond to actual mm)
• After changing the value, click [Save] → click [Reset] at the top to apply the new home position

There is no software option to adjust the Y-axis front/back direction. The bolts securing the capping station must be loosened and the position set manually by hand.

• Loosening the two bolts above the waste ink tank creates a small amount of play to move the capping station forward and back
• While running inkload (pumping) from the software, slowly shift the capping station by hand until ink begins flowing into the waste ink tank
• Tighten the bolts at that position and re-verify pumping — also confirm ink flows properly during cleaning
• Since all three heads (color, white, varnish) must pump correctly, this process can take longer than expected

This sets how high the captop rises to seal against the print head. The reference value is 5.

• Too low (3–4): captop and head will not seal, causing pumping to fail
• Too high (6–7): head bottom contacts the captop pad, causing damper ink to drain out and creating ink shortage during printing
• Path: [Menu] → [Printhead cleaning setting] → [Elevator mechanism(mm)] → double-click [Capping height] → enter value → [OK]

A real field case:

• About two weeks after delivery, LC or LM suddenly dropped out during printing
• Replacing the entire ink line did not help — the same problem returned within two days
• Replacing the captop temporarily fixed things, but the same problem recurred 1–2 weeks later in a repeating pattern
• The root cause was the capping station height being set too high — as the captop rubber blade weakened over time, the head bottom began contacting the captop pad, continuously draining damper ink
• Changing the height value from 6 to 5 resolved everything — no parts replacement needed.

Sometimes ink flows into the waste tank but carries a lot of bubbles with it. This happens when the head bottom and captop are not precisely aligned and air is pulled in through micro gaps at the edges.

• Pour white ink into the captop, then move the head to the left while capped to inspect the captop contact mark on the head bottom
• Use the ink mark on the head surface as a reference to correct the captop position
• For minor adjustments, loosen the two bolts securing only the captop rather than moving the entire capping station

The captop rubber blade is pressing down on the last channel nozzles. Because it is pressing against the head surface, the seal is maintained and inkload (pumping) works fine — but the rubber blade is blocking the nozzle row of the last channel, preventing ink from firing.

• Since pumping and cleaning both appear normal while only one channel fails, it took a long time to identify the cause in the field
• If only the last channel is not firing, always consider this as a possible cause

If inkload (pumping) fails, cleaning cannot proceed and printing becomes impossible. Pumping failures can be caused by multiple factors — captop, damper, pump motor, and head/captop position — so checking each in order is essential.