Encoder-based control of printhead firing in a label printer

• Main Authors: Fisher, Richard P, Gale, David T, Kremers, Douglas R, Workman, Daniel K
• Format: Patent
• Language: English
• Published: 07.09.2004

This invention relates generally to media printing systems. More particularly, the invention relates to a media printing system having an encoder that monitors the actual position of the media in order to control the firing of the printhead for the printing system. A method of determining the position of a label media and printing to the label media based on the label media position is disclosed. The method includes using an encoder to track the position of the label media. As the label media advances during printing, an encoder shaft rotates with an encoder traction roller upon which the label media rides. As the encoder shaft rotates, optical reflections that occur within the encoder are interrupted, each interruption corresponding to a desired media travel distance. When the optical reflection is interrupted, the encoder sends a signal to the controller, which then sends a control signal to fire the printhead, and consequently the label media is thermally printed. The system is useful in thermal printer systems to provide more accurate position information of the label media, and consequently, more accurate printing. In this manner, with the encoder tracking the motion of the media, the timing of the printing of the label media is determined upon the actual position of the label media itself.