The core is a necessary part during production of thermal paper rolls. There are several types of cores used in paper rolls. Basically, they are divided into 2 types according to the material. They are paper cores and plastic cores.
1. Paper cores
Paper cores are produced through rolling paper material with glue. They can roll into different sizes. The inner core diameter for thermal paper roll is 13mm, 16mm and 25mm. The thickness of a core is usually at least 3mm to keep it strong. Thus the popular sizes are 13x19mm, 16x24mm, 25x34mm.
2. Plastic cores
The plastic cores are extruded then cut to length size or can be injection molded to fixed size. Unlike the paper core, they can not be rolled into different thickness. Their sizes are normally fixed.
Two types of plastic cores are used for thermal paper rolls. One is plastic solid core, like 13x17mm solid core. The other is plastic honeycomb core, like 13x22mm honeycomb core.
For some printing machines, the core need to be in specific shape, such as hexagon shape.
In all, plastic cores can be in different colors like white, black, yellow, green, blue, etc.
Last not the least, with the development of technology, cores can be eliminated both for production and usage. Coreless thermal paper rolls are now on the trend. It decreases the production cost and save space for merchant.