Taskalfa 420i dots while scanning

**pureflip428** · 10-09-2015

I am working on a machine (TASKalfa 420i has about 182,000 pages printed so far) that has dots while scanning through the document processor. The dots appear only while scanning, and not when copying. The dots are throughout the whole page. Imagine old comics that were illustrated with dots. Sort of like that except a lot smaller dots on the whole page. Scanning is set to send to email. There is a 3500i on the same network that also scans to email same as this machine but has no problems. This is what I have done so far but nothing has fixed the issue so far.

I ran maintenance mode
- Ran U425 & U411
Flushed the firmware
Replaced ISU
- replacing the ISU resulted in having only the top half of the page with dots. The bottom half was clear
Cleaned slit glass
Cleaned white reference strip under plate glass
Cleaned all mirrors
(all cleaning was with a dry cloth towel)
Changed scanning resolution from 200x200 dpi to 600x600dpi
- Changing the resolution resulted in finer or smaller dots on the page. Imagine zooming out on the page.

Since the new ISU did not fix the problem, the old one was put back in and left with the following scan settings.

File Format : PDF
Resolution : 600x600dpi
Quality : Text + Photo

Attached is a scan of a print of what was scanned. (Machine is not at my location and I was not able to scan straight to my own email)

**Kyo fan** · 10-12-2015

I've had something similar to this and it was that i left the mirrors not aligned after i cleaned them. Check the mirrors, and press each down on both ends. You said you did U411 (Adjust DP automatically). Do you have all 3 charts needed for it?

**kjg** · 10-12-2015

Try scanning something not printed on the 420i and see if you still have the dots.
I have seen that before on machines going back to falcon II's scanning printed documents.
It may be picking up background on the print you have made. You may need to adjust print density or do gray adjust.

**copydocinc** · 10-13-2015

I'm wondering if it does it when laying page on the glass, instead of the doc feeder. If not, that would eliminate a few things.
and
Look closely at the scanned copies of the same document to see if the dots are uniform or random from one page to the other, if uniform the post above has merit, that the original being scanned isn't clean.

**SamuelBlake72** · 01-30-2018

I am having the same problem with a 3500i. We have tried the sata cable from the main PCB to the scanner board. Have also tried replacing both boards. Lost on what to do next. Problem occurs when scanning a document either to doc box or to folder and email from glass or df.