The engine determines the printing velocity of a printer. Nowadays, some printers incorporate an in-line scanner to scan each page as it is printed and to diagnose print quality defects in real time. However, the velocity of the paper may vary as the page is being printed. When the printer’s printing velocity is variable, and the scanner is still scanning at a constant rate, the scanned printed image will be a stretched and compressed image. This stretched and compressed scanned image is different from the real printed image. It is difficult to detect and analyze the print quality directly from this stretched and compressed scanned image. In this article, we present the printing velocity simulation and estimation. The article is organized into three parts: the first part introduces the print speed simulation tool; the second part introduces the specifically designed test page for printing velocity estimation; the third part introduces the core algorithm: the print velocity estimation algorithm. The printing velocity estimation algorithm contains image processing methods, and it uses the Dynamic Time Warping (DTW) algorithm [1] to accurately and consistently estimate the exact printing speed. In the end, we will show the results of this algorithm. This printing velocity estimation algorithm with the specifically designed test page can accurately estimate the printing velocity. Besides, the printing velocity estimation algorithm also works for complex customer content.