Printing systems such as copiers, printers, facsimile devices or other systems having a print engine for creating visual images, graphics, texts, etc. on a page or other printable medium typically include various feeding systems for introducing original image media or printable media into the system. Examples include document feeders into or onto which a user inserts original documents from which images are obtained, as well as so-called bypass trays for introducing printable media into a printing system. These media feeders typically include media guide structures with which the inserted media is registered by moving one or both of the guides to engage opposite sides of the media, thereby fixing the location of the media relative to the entry path into the system. Advanced printing systems often provide for automatic or semi-automatic identification of the width of the inserted media according to the relative location of the media guides, and use the size information for further processing of the media within the system. Conventional approaches for media width identification include manual identification with no sensing, wherein a user is prompted to input the media size and orientation, provision of a series of opto-interrupt sensors with sensor flag arrays connected to moving guides, as well as use of potentiometers connected to one or both of the moving media guides. However, the resolution of these automated width measurements systems is limited and is subject to mechanical and electrical tolerance variations, whereby discriminating between standard media sizes is often difficult and these systems typically require calibration procedures to ensure correct identification of the inserted media width. Thus, there remains a need for improved media feeding and width sensing techniques and apparatus by which the automatic or semi-automatic determination of media width can be improved and by which the need for width sensing system calibration can be mitigated.
USPTO Backgrounds
USPTO Backgrounds