It looks to me as the your filament isn’t flowing out smoothly after a little bit of time. Is anything binding the filament as it comes off your spool? Perhaps it’s a little tangled on the spool itself, it happens some time. How about the hobbled gear? Is it grinding the filament? Heat can creep up from the print head and soften the filament too much where the Hobbes bolt gear grabs it, what print head are you using and what type of filament? What temperature are you printing at?
Don’t forget to add which direction you image was printed in… right to left or left to right would have very different solutions.
I’m pretty sure that there is a problem with the heat creeping up… sometimes been I pull the fillament out I can see that it was lodged somewhere else… It also has a problem where the hobbed bolt is grinding away at the fillament itself stopping itself from extruding… I’m printing PLA at 220°C… I also think it might have something to do with the auto bed levelling, as the bed might be closer to the nozzle in the middle…
It printed from right to left… It starts off fine but then the fillament starts to blob up…
It seems you have a fair grasp on the situation, not sure how we can help too much. If the nozzle is too close to the bed you’ll experience too much back pressure and that will surely cause you problems, especially with heat creeping low melting temp PLA. Of course try leveling the bed. Lowering your print temperature may help a little. Try a desk fan to blow away the excess heat. Try some other filament like PETG if you can as it may be a little more forgiving in this situation.
220 seems high for PLA, I print mine at 210-205 first layer then 205-200 for the rest of the layers.
PLA loves cooling! First layer either off or a low value like 25%, second layer 50%, and the rest at 100%. I started out using a desk fan but the idiot operator kept forgetting to turn the fan off for the first layer and on for the rest .
Since my TAZ 6 is connected to an RPi 3B running OctoPrint, I added a hat to the RPi and have 2 variable speed fans mounted to the frame of the TAZ 6 which mirror the M106 setting(s).
Not to say that there isn’t a bed leveling problem, but this doesn’t look like an issue of the nozzle being too close. When I’ve had that in extreme cases it has been a literal ribbon. If this is heat creep, is there an issue with the hot-end cooling fan? 220°C isn’t that hot and is still within range for some PLA. As mentioned, the filament could be getting bound up on the spool or somewhere else in the line.
I was having similar issues. 1st, check your hot end cooling fans. Make sure the labels are facing toward the hot end. From the factory mine were reversed with label facing out so instead of blowing on the hot end it was drawing air from the hot end side. Also I increased my temp. Using MatterHackers PLA standard default printing temp set to 230, print temp initial layer 235, initial print temp and final print temp 230 and build plate temp 60. MH suggests 220 max for print temp and 50 for bed temp however since I switched the fans around (probably what fixed the problem) and increased my temps have not had any issues.