The Design of Digital Inkjet Printing Control System Based on FPGA

Aiming at the high cost and low real-time performance of adjusting image grayscale in traditional inkjet printing systems, a digital inkjet printing Control system based on FPGA(Field Programmable Gate Array) has been designed to balance the speed differences across clock domains between the FPGA and SDRAM(Synchronous Dynamic Random Access Memory), achieving real-time adjusting the grayscale of images in a single print head devices. The system selects FPGA as the main control chip and SDRAM as the memory, simplifies the SDRAM interface using asynchronous FIFO(First Input First Output), and inputs images through the serial port and stores them in SDRAM. Before printing each column of pixel data, a DAC(Digital-to-Analog Conversion) circuit and a proportional amplification circuit are used to generate an adjustable amplitude drive voltage. By adjusting the amplitude of the drive voltage, the ink droplet amount for each column of pixels can be controlled during printing. The system experimental platform that has been constructed verifies that the system possesses characteristics of strong real-time grayscale adjustment, low hardware cost, and high reliability. It can satisfy the requirement of quick and small-batch printing with grayscale adjustment, and it has significant importance and value in advancing technology in the inkjet printing field.