The machine performs shading correction to correct any discrepancy in the output of the CCD. It performs shading correction at power-on and or for each job.

5.3.7.6 Shading Adjustment

iR C3380i / iR C3380 / iR C2880i / iR C2880 / iR C3580 / iR C3580i / iR C3080 / iR C3080i

The machine measures the density of the standard while plate, and uses the result as density data. The data is then subjected to computation to obtain the target

value for use during shading correction.

5.3.7.7 Shading Correction

iR C3380i / iR C3380 / iR C2880i / iR C2880 / iR C3580 / iR C3580i / iR C3080 / iR C3080i

The machine executes shading correction for each scan of the original. It measures the density of the standard white plate, and compares the measurement against

the target value stored in the shading correction circuit; the machine then sets up the difference as the shading correction value, and uses it to correct any variation

among CCD pixel when scanning the originals, thus evening out the image density levels.

5-18

CCD output

Target value

Measurement

Standard while plate

F-5-32

Characteristics

after correction

Characteristics

before correction

White