Two more things to check:
1. - If the humidity in my room is less than 40%, it acts like that every time; and
2. - Take the front cover off and check the white ink waste line. Put some cleaning fluid in the capping station and use a screwdriver to manually turn the pump (not going into a lot of detail here because I'm sure you're familiar with the parts and pieces). If the fluid is going all the way to the waste bottle, there's no blockage there, but if not...
There are connectors in the waste tubing between the capping station and the waste bottle. Sometimes the tubing is pulled far enough into the wall area (toward the waste ink bottle) that you can't see these connectors. That's where one clog is. Whenever I leave my machine too long or I'm getting little or no white in prints, this is the first place I look now. Another indicator - when you turn the screwdriver, sometimes you'll hear a pop back from the suction (and you'll see it if you've got the cover off). So here's what I do:
- Disconnect the white line from that connector, and push cleaning fluid from the connector to the waste ink bottle to make sure there's not another clog downline.
- Put cleaning fluid in the capping station and turn the screwdriver to see if you're lucky enough to just have a clog at the end, and just flush the clog out into a small container.
- Most of the time there's also a clog just under the capping station that you can't get to. I put cleaning fluid in the capping station, then push cleaning fluid up the hose with firm pressure and hold it firm while clamping off the line with a hemostat to hold the cleaning fluid in the line. Leave that for 2 hours to overnight depending how bad the clog is.
- Unclamp the line and drain it onto a paper towel or something. Then try to pull the clog with a syringe (probably won't work, but you might get lucky).
- Fill the syringe with cleaning solution and push-pull the solution on the line to see if you can get the clog to move down where you can see it. Once you release, it's going to go back up there and hide, so you need help or good coordination. If you can pull the clog down far enough to see it, pinch above it with your finger so it won't go back up when you release the syringe. Don't let go, there's still enough vacuum to suck the clog back up.
- Get your fingers wet while still holding the clog and slip it down the tube and out onto the towel.
- Repeat a combination of these actions until you get the clog out. You'll figure it out pretty quickly.
- Manually pump (with the screwdriver) a bunch of cleaning fluid through the capping station to clean out any smaller chunks of white ink. Connect all the lines and run more fluid into the waste bottle, fire it up and run some ink purges and you're done.
I use two types of cleaning solution, the DTG brand which is ammonia based, and my own mix of 50/50 Simple Green and hot water. Usually the Simple Green solution is for when I'm doing something like this where I'll be using a lot of cleaning fluid and don't want to waste the DTG stuff.
