Design Of High-resolution Inkjet Printer Based On Embedded Linux

With the improvement of living standards,people pay more and more attention to the production date and effective date of the products,and manufacturers pay more and more attention to additional information such as product anti-counterfeiting labels and brand identification.At the same time,with the development of barcode technology and the popularity of mobile terminal identification softwares,the systems based on “one product,one code” for management,traceability,anti-counterfeiting and marketing are receiving widespread attention.The application of inkjet marking industry is getting wider and wider,and the market demand of inkjet printers is increasing.The foreign inkjet industry started early,technology has been quite mature,but the domestic started late,technology is backward,and the market share is small.It is necessary to further study and develop the technology of inkjet printer with independent intellectual property rights.Combining embedded technology,sensing and detection technology and bar code technology,a high-resolution inkjet printer based on embedded Linux is developed in this paper,which realizes the printing of text,pattern,variable QR code,variable counter and so on.According to the function and performance requirements of high resolution inkjet printer,the system is divided into the host system base on ARM processor and the slave system base on FPGA processor.The slave system accomplishes the following tasks.Photoelectric switch detects the position and an incremental encoder is used to measure the speed and direction of the object to be printed.Serial peripheral interface control module with data verification function is dedign to realize data transmission between the host and slave system.SDRAM control module is dedign to realize memory expansion and print data buffering.According to the timing requirement,write driver with verilog programming language to realize the control of the nozzle.Some exception handling processing module and data processing module is considered to assist the printing.According to function classification and users’ habits,the host system is divided into five parts including printing control module,data editing module,parameter setting module,system-setting module and status display module.The touch screen as the interaction interface is used to realize the free editing of text,pattern,barcode,and counter.Parameter setting can be supported,such as printing speed,printing delay,printing direction,nozzle selection and so on.In printing control module,a method for improving variable data printing speed was proposed,which realized partial update and accurate replacement of print data in SDRAM memory,used multi-thread and asynchronous notification mode to make the data update request respond in time,and extracted print data based on BMP image.In order to improve the recognition rate of QR code printed by inkjet printer,the encoding principle of QR code is studied.An optimal coding mode selection algorithm is presented to increase the QR code encoding density.And then a QR code generation algorithm suitable for the inkjet printer is written that can effectively improve the recognition rate of QR code printed by inkjet printer.Finally,the schematic and PCB were designed and the function and performance of the high-resolution inkjet printer were verified and tested.The experimental result showed that the expected printing function has been achieved.Under the condition of resolution of 300 DPI,it can print 186 QR codes per minute and the recognition rate is above 99.96%.Through 40,000 times of continuous printing work,the stability of the system has been proved and the expected performance index was achieved.