exposure magnification correction explanation on QSS minilab

[forrest]

Can anyone explain to me how exactly the exposure magnification correction works on the QSS minilabs(we have a QSS 34pro)? More specifically if I wanted to adjust the image width on a 5 inch print without effecting larger sizes that much and vice versa. Also it seems like the part of the image closer to the sides is more stretched out than the center part of the image, how would I bring the outer parts of the image in without(or just sightly)  effecting the center?

[Dave S]

The exposure magnification should be carried out on the widest paper that you use (normally 12 inch paper).You can't adjust individual paper widths, it's automatically calculated from the 12 inch correction that you input.

Check the pressure guide rollers are clean.

The problem may be caused by incorrect mechanical adjustment of the pressure guide rollers. Make a test print using the Exposure Advance Adjustment, Exposure Advance Pressure Inlet Roller Test and Exposure Advance Pressure Exit Roller Test, use 12 inch paper for the test. Measure between the 0mm line and the 254mm line on the left and right side of the test print. The difference should be within 0.2 mm between the left and right sides.

If you are getting white lines on 5 inch prints, firstly check the paper magazine centre core and exit guide widths are set correctly (it's very easy to be 1 notch out) If all good it will most likely be the exposure centre correction (for each magazine) or the Arm Unit 1 Zigzagging Correction that needs to be adjusted.

Edited March 23, 2017 by Dave S

[forrest]

So for when I'm adjusting the exposure magnification setting using the 12 inch paper which marking should I be adjusting at?(70, 110, 130, 160, 190, or  290)

[Dave S]

Measure between the 160 lines.

Select the 160 width, enter the measured value.

Then make a confirmation print and ensure it is actually 160mm.