基于嵌入式Linux的LED打印机数据处理机的设计与实现

发布时间：2018-03-02 13:44

本文选题：LED打印机　切入点：U盘打印　出处：《西安电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：伴随着计算机技术的快速发展,打印机得到了广泛的使用,用户对打印机在打印速度,打印质量以及U盘打印等功能都有需求。LED打印机是近十多年发展起来的,将LED技术应用到打印机上,使其具有了可靠性高、打印速度快、成像效果好、整体体积小、节能环保等特点。本文研究在LED打印机控制系统中嵌入Linux操作系统作为数据处理机,完成数据解析、图像处理、打印控制等功能,提升打印机性能。本文的创新之处在于,数据处理机结合打印控制器的其它模块不仅可以完成基本打印功能,还可以完成从移动存储设备直接打印PDF、TIF、JPEG、BMP图像的功能。Linux操作系统作为数据处理机的嵌入式软件系统,移植Linux操作系统的主要工作包括搭建开发环境、裁剪内核以及构建根文件系统。搭建开发环境包括宿主机安装以及交叉编译工具链的安装。裁剪内核包括添加USB从口打印机驱动以及编写和添加GPMC驱动等工作。根文件系统的构建包括了修改配置文件以及添加交叉编译的应用程序等工作。数据处理机运行了三个与打印控制相关的进程:打印机守护进程、U盘直接打印进程和打印机状态显示进程。打印机守护进程是以Linux操作系统的守护进程的形式在后台运行。打印机守护进程和打印机状态显示进程开机自启动,打印机守护进程首先初始化工作环境,每次开机只需要初始化一次;初始化结束后,打印机守护进程进入一个守护循环来等待即将到来的数据连接、接收并解析数据以及设置打印参数等操作。一次循环包括设置多路IO、解析PCL文件、发送数据、以及打印结束清理环境等操作。打印机状态显示进程显示打印机的状态,当U盘插入打印机时,显示U盘的文件目录,用户可以脱离主机选择文件和设置打印参数打印对应的文件。U盘打印进程默认不启动,当用户插入U盘,选择了打印文件,打印机守护进程启动U盘打印进程。U盘打印进程主要工作包括图像处理、半色调、压缩、添加PCL控制命令等操作,然后将打印数据发送给打印机守护进程。在数据处理机上做图像处理,需要移植图像处理库Mupdf,Mupdf是一个C语言库,方便移植,并且Mupdf小巧、快速、而且功能完备。Mupdf可以解析常用的图像文件PDF、JPEG、TIF。此外在数据处理机上还需结合FPGA的半色调模块和压缩模块以及异步FIFO等资源对位图进行半色调和压缩处理。通过安装有安全打印驱动的麒麟操作系统的主机或者U盘分别对移植了嵌入式数据处理机的LED打印机进行测试,证明可嵌入式数据处理机具备了数据解析、图像解析、打印控制等功能,各项技术指标符合预期。
[Abstract]:With the rapid development of computer technology, printers have been widely used. Users have a demand for printing speed, printing quality, U disk printing and other functions. The LED technology is applied to the printer, which has the advantages of high reliability, fast printing speed, good imaging effect, small overall volume, energy saving and environmental protection. This paper studies the embedding of Linux operating system as a data processor in the LED printer control system. Complete data analysis, image processing, printing control and other functions, improve the performance of the printer. The innovation of this paper is that the data processor combined with other modules of the print controller can not only complete the basic printing function, The function of printing the image directly from the mobile storage device can also be completed. The Linux operating system can be used as the embedded software system of the data processor. The main work of transplanting the Linux operating system includes setting up the development environment. The kernel is clipped and the root file system is built. The development environment includes the installation of host host and the installation of cross-compiling tool chain. The clipping kernel includes adding USB slave printer driver and writing and adding GPMC driver. The construction of the root file system includes modifying the configuration file and adding cross-compiled applications. The data processor runs three processes related to print control: the printer daemon and the U disk direct print process. Printer daemons run in the background as daemons of the Linux operating system. The printer daemon initializes the working environment only once at a time; after initialization, the printer daemon enters a daemon loop to wait for the incoming data connection. A loop includes setting up multichannel IOs, parsing PCL files, sending data, and printing end cleanup environment. The printer status display process shows the printer's status. When the U disk is inserted into the printer, the file directory of the U disk is displayed. The user can select the file and set the print parameter to print the corresponding file. The U disk printing process does not start by default. When the user inserts the U disk, the print file is selected. The printer daemon starts the U disk printing process. The main work of the U disk printing process includes image processing, halftone, compression, add PCL control command, etc. Then send the print data to the printer daemon. To do image processing on the data processing machine, we need to transplant the image processing library MupdfMupdf is a C language library, easy to transplant, and Mupdf is small and fast. Moreover, the function of .Mupdf can parse common image file PDF / JPEGG / TIF. in addition, the half-tone module and compression module of FPGA and asynchronous FIFO should be used in the data processing machine. The bitmap can be halftone and compressed by installing. The host or U disk of the Kirin operating system, which has a secure print drive, tests the LED printer that has been transplanted into an embedded data processor. It is proved that the embedded data processor has the functions of data parsing, image parsing and printing control.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TP334.8

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