Abstract: A printer capable of adjusting a clearance between an inkjet nozzle and a printing material surface is provided for printing not only on regular stationery, but also on thick, non-flexible printing material. This printer equipped an operating menu for selecting a printing function comprises a separable lower and upper frames, a mechanism for adjusting the inkjet clearance, a sensor for detecting the printing material thickness, a computer program for controlling the inkjet clearance, an actuator and power transmitting mechanism for vertically moving the upper frame. Alternatively, an electromagnetic actuator is provided for vertical operation of the upper frame. A process for adjusting the inkjet clearance comprises the steps of: centering and detecting a thickness, adjusting the clearance, detecting the position of the printing material, verifying the printing position comparing with the pre-loaded data, adjusting the position to coincide with the detected position, and printing on the printing subject.