FPGA Design Of Data Processing And Printing Control System For High-speed Digital Inkjet Printer

Compared to traditional screen printing, digital printing has many significant advantages, such as high image precision, energy-efficient, low pollution and short delivery cycle. Therefore, digital printing may become the main printing technology in future. The key parts in digital printing technology are image data processing and printing control. Before the year2009, most digital inkjet printers applied PC to process image data. Because PC couldn’t transpose and output large quantities of image data bit-by-bit in real-time, the printing speed of digital inkjet printer and its application were both limited. Sharply improving the printing speed of digital inkjet printer becomes a pressing issue.An embedded system based on MPC8548E processor and Virtex-5series FPGA is researched and developed in this thesis. MPC8548E receives image data from PC by Gigabit Ethernet and decompresses these data. FPGA is responsible for bit-by-bit transposition and printing control. Image data is transmitted between processor and FPGA through high-speed serial RapidIO1.x interface. Three independent DDR2controllers are instantiated inside FPGA, collaboratively working mechanism among these controllers and read/write strategy of every controller are designed in order to improve output bandwidth. DDR2controller’s read/write efficiency is increased by dividing image data into small blocks and reading/writing these blocks via burst transmission. Effective transposition logic is designed by using registers and Block RAM resources within FPGA. According to printing timing of the specific printhead, output FIFO and control logic which is directed by user setups are designed.Testing results indicate that input bandwidth of FPGA is341Mbps and transposition bandwidth is315Mbp. Theoretical maximum output bandwidth is calculated to be327Mbps, and actual output bandwidth is tested up to326.4Mbps. When equipped with four KJ4B printheads and printing with eight colors in600dpi x600dpi resolution, the printing speed of digital inkjet printer which uses this data processing and printing control system as its key part reaches249m2/h. Compared with digital inkjet printers which utilize PC, the printing speed is dramatically improved under the same conditions.