Precise and accurate motion control of media through a printer is a critical element of image quality. Media advance errors of a fraction of a dot row can be visible to the eye as banding.Competitive pressure for higher print quality and higher throughput have driven inkjet printer designs to use wider print swaths in combination with reduced-pass print modes that together place unprecedented precision and accuracy requirements on the motion control of the media through a printer.To meet this demand and overcome the practical limit of indirect measurements from encoder-based systems, HP has invented and developed a sensor that provides a direct measurement of the actual media advance based on the Optical Navigation Technology: the HP Optical Media Advance Sensor (“OMAS”). OMAS is a tiny, custom “machine vision” system that takes digital images of the microscopic texture on the backside of the media as it moves through the printer. Successive images of the surface texture are correlated in real time to compute the media motion with unprecedented accuracy.Because OMAS provides a direct measurement of media advance, it eliminates many variable and complex factors that affect the media drive system. It facilitates to achieve accurate vector lengths, consistent image quality and better line straightness for a broad diversity of printing media and maintain them across a wide range of temperature and humidity conditions, providing dependable performance over the printer's life in production printing environments.HP's Optical Media Advance Sensor and the associated navigation and servo correction algorithms first introduced in the HP Designjet Z6100 and since continuously upgraded in following Designjet printers to enable faster media move and improved system reliability over broader operating ranges, can equally be beneficial to other systems with very precise and accurate motion control requirements at high throughput.