Sharp MX-7090 (8090) skew

[xcore]

Having a strange skew issue (see attachement) when printing on heavy custom size stock (280 gsm) from the bypass tray. Paper is 320x460 mm (not 320x450), and I have added a custom size in the menu. Printing with Heavy4 profile.

Now, if I trim it to 320x450 (SRA3), then it prints almost perfectly (little bit of skew, about 1 mm).

IMG_20211113_140100.jpg

[xcore]

Re: Sharp MX-7090 (8090) skew

One more strange thing is that if I print duplex on this paper, then the duplex side is printed ok. Like it prints crap on the first go and then figures out how to print on another side...

[Prints Charming]

Re: Sharp MX-7090 (8090) skew

Does this happen on Plain Paper?
You can enable auto correction for skew in the Administrator Adjustment Settings for the Pro series devices.
Go to Image Position/Ratio/Area Adjustment menu, then Off Center Adjustment. Check default value 50 in Print Off Center Adjustment, and enable Main & Sub Scan Auto Adjustment in Auto Centering Adjustment Menu.

[xcore]

Re: Sharp MX-7090 (8090) skew

On plain paper it prints fine. Auto centre thing is enabled, actually when I disable it prints a little bit better but still skewed.

See illustration of how it prints. Gray is how it should print and red is how it prints.

Screenshot 2021-11-16 at 13.05.17.jpg

[spanky]

Re: Sharp MX-7090 (8090) skew

Go to simulation 51-2 and find the adjustment for heavy paper on the bypass.

Increase this number a little and then check the print for changes.

This increases the paper buckle at the registration roller to help correct a crooked feed issue.

[xcore]

Re: Sharp MX-7090 (8090) skew

OK I toyed with settings and it's printing more or less straight. I also created a custom paper profile and calibrated it so it prints dead center (using Side1/2, XY Print Position).

I try to print the next day with the same settings and it is off center again... it looks like if it sits idle for a while it shifts/drifts and I have to re-calibrate Side1/2 XY Print Position each time.

Any ideas what could be causing this?


P.S. Auto Centering is disabled. I does not work for me on this paper or tray.