Portable printer and portable printing system

A portable printer comprising:

• a main body in a portable form configured to accommodate a cartridge comprising a nozzle that prints an image by delivering a printing material to a target having a soft or hard surface;
• a seating part that is provided to be exposed to an outside from a lower portion of the main body to face a surface of the target and surround the nozzle at least partially;
• a roller provided at each of a front and a rear of the nozzle at the lower portion of the main body, based on a direction in which the main body moves along the surface of the target to deliver the printing material to the target;
• a controller configured to control delivery of the printing material by the nozzle;
• and
• a printing adjustment unit that is configured to adjust a height difference between the nozzle and the surface of the target by moving the roller in inner and outer directions of the main body to adjust a height difference between the nozzle and the roller,
• wherein a plurality of the nozzles are provided and comprise a first nozzle and a second nozzle of different sizes,
• wherein the controller is configured to control the printing material to be delivered by the first nozzle and the second nozzle, and control the printing material to be delivered by the first nozzle among the first and second nozzles,
• wherein the printing adjustment unit is configured to move the seating part in the inner and outer directions of the main body, and
• wherein the roller is configured to move integrally with the seating part.