Three rules cover every model: print side down, a few millimetres of paper left poking out of the slot, and the cover closed firmly. Get those right and the printer reads the roll and carries on. Get the first one wrong and it will feed paper and print nothing. How you physically open the machine depends on which one you own — pocket models slide, 2-inch models have a hinged compartment with side guides.
Pocket models: D11, D110, D101
- Slide the button on the cover sideways to release it and lift the cover.
- Drop the roll into the bin with the sticker side facing down.
- Pull the leading label out through the tear-off slot so roughly 3–5mm sits outside.
- Close the cover until it clicks, with that paper still poking out.
That last detail is the one people skip. If nothing is left outside the slot, the feed has nothing to grip and the printer either does not respond or feeds without printing. Rolls for these live in the D-series range — see the D110 if you are still choosing.
2-inch models: B1, B1 Pro, B2, B2 Pro, B21, B21 Pro
- Press the catch on the side to release the paper compartment and open it.
- Push the two guides apart, then sit the roll in with the print side facing down.
- Slide the guides back in until they hold the roll without pinching it — this is what keeps printing straight.
- Feed the first label out of the paper exit and close the lid.
The B21 Pro is the easiest of these: its no-paper-core design means you slide the clip open, drop the roll in and close, with no spindle to thread. Stock for all of them is in the B1 and B21 roll range, and the B1 Pro takes exactly the same rolls.
Wide and desktop: B31, B4, K3
Same principle, bigger bin. The B4 holds its roll internally, so a 100×150mm courier roll sits inside rather than hanging off the back. The K3 takes internal rolls and fanfold stacks fed from behind — if you are using fanfold, feed it in through the rear slot rather than trying to coil it into the bin.
Continuous stock on the H1S
The H1S loads the same way, but continuous rolls have no gaps between labels. There is nothing to line up — feed it out of the slot, close the cover, and cut each label to length with the built-in blade after printing.
The N1 and M2 need a ribbon too
These are thermal transfer, so there are two things to load: the PET label roll and a ribbon. Seat the ribbon on its spindles and take up any slack before closing — a loose ribbon creases and prints patchy. If you loaded labels but forgot the ribbon, you get blank labels, exactly as if the roll were upside down. Our N1 and M2 consumables guide covers which goes with which, and the N1 product page lists its sizes.
Three things that actually go wrong
- Roll in upside down. Direct thermal only darkens the coated side. Blank labels, every time — our guide to printing blank labels works through it.
- Nothing left outside the slot. Causes odd feeding or no response at all.
- Guides too tight or too loose. Too tight drags the paper, too loose lets it wander. Snug, not clamped.
Change the roll before it runs out
Genuine NIIMBOT rolls carry an RFID chip, so the printer reads the size the moment you close the lid and the app sets itself up — no measuring. Keep a spare from all refills within reach, because nothing wastes time like running dry halfway through a batch. For model-specific diagrams, our printer operation guide has them, and every printer ships from our Singapore warehouse with a 1-year local warranty.