Image scanning apparatus

摘要

In a scanning apparatus, a controller is configured to obtain black reference data, compensated data based on digital data (scan data) by scanning a reference member with the light source turned off, and the black reference data. The controller further compares the compensated data with a first particular value. The controller executes the compensated data obtaining process with setting the light amount adjustment value to be a smaller value when the compensated data is greater than the first particular value, while with setting the light amount adjustment value to be a greater value when the compensated data is less than the first particular value. Further, the controller sets the light amount adjustment value to be a scan-time light amount adjustment value when the light amount adjustment value is equal to the first particular value. Then, the controller executes a scanning process according to the scan-time light amount adjustment value.

主权项

1. A scanning apparatus, comprising:
a reference member arranged on a conveying passage through which an original sheet subject to scan is conveyed; a scanning device configured to scan an image on the original sheet when the original sheet passes the reference member, the scanning device including a light source and a light receiver configured receive reflected light which is light emitted by the light source and reflected by the original sheet; a convertor configured to covert analog signals output by the scanning device into digital data for respective pixels in one line of the scanning device; a compensator configured to calculate compensation data based on the digital data and black reference data, the compensation data being data removing variation of the black reference data of respective pixels from the digital data; a setting device configured to set a light amount setting value used to adjust a light amount of the light emitted by the light source; and a controller, wherein the controller is configured to execute:
a black reference data obtaining process in which the controller obtains the digital data by scanning the reference member with the light source turned off as the black reference data;a compensated data obtaining process in which the controller obtains compensated data based on the digital data which is obtained by scanning the reference member according to the light amount setting value with the light source turned off, and the black reference data;a light adjustment process in which the controller:compares the compensated data with a first particular value and:executes the compensated data obtaining process with setting the light amount adjustment value to be a smaller value when the compensated data is greater than the first particular value;executes the compensated data obtaining process with setting the light amount adjustment value to be a greater value when the compensated data is less than the first particular value; andsets the light amount adjustment value to be a scan-time light amount adjustment value which is used for scanning when the light amount adjustment value is equal to the first particular value; anda scanning process in which the controller causes the light source to emit light according to the scan-time light amount adjustment value.