Densitometric sensing device for use in printing presses

摘要

Method and apparatus for scanning an ink test strip printed on a sheet, the sheet being positioned on a table traversed in two directions by a scanning head. The table includes guide means including a bar for positioning the sheet in a first dimension and an index mark for positioning the sheet and its associated test strip in a second dimension. The scanning head indexes to the index mark which physically establishes a first coordinate for the test strip. Thereupon, the scanning head indexes in a second direction to automatically locate the test strip based on the size of the test strip as sensed by the densitometric sensing device associated with the scanning head. Having located the second coordinate Ys for the initial test patch of the test strip, the system then initiates the scan along the test strip to measure the optical density of each test patch relating to each printed zone on the sheet.