Patent ID: 9001318
Filing Date: 2015-04-07
Classification: G01N,G07D

Abstract:
1. A method for a soiling check of a window of a measuring apparatus that is formed for checking a sheet material that is transported along a transport path past the measuring apparatus, and which has at least one light source for irradiating the sheet material, at least one sensor line for detecting a light emanating from the sheet material, the sensor line having at least the width of the sheet material, at least one evaluation device for the evaluation of a light signal that was detected by the sensor line upon the detection of the light, and at least one window between the sensor line and the transport path of the sheet material, wherein in phases in which the sheet material is in a detection region of the sensor line, the method comprises the measuring apparatus carrying out a check of the sheet material, upon which there is checked only at least one partial region of each sheet of the sheet material, which partial region has a specified length and width and altogether is narrower than the width of the sheet material, through detection and evaluation of a light emanating from the at least one partial region of the sheet, and wherein in phases in which no sheet material is in the detection region of the sensor line, a light emanating from the window is detected and evaluated for the soiling check of the window, wherein, the soiling check of the window does not evaluate the entire area of the window but only evaluates a light that emanates from a partial region of the window through which, upon the check of the sheet material, the light reaches the sensor line and which with respect to its width and its location in a beam path of the light corresponds to that at least one partial region of the sheet material that is checked upon the check of the sheet material.