ADF scan image start straight progressively skewed towards the end of page

[Chee1]

My printer scanner and the ADF was working perfectly and out of the sudden, the scanning failed. I sent it in for warranty and I must thank HP for being decisive to replace it with a new printer.

The new replacement unit flatbed/glass scan is working well. HOWEVER, it has a problem with ADF where the scanned image starts straight for the first 30% of the page, and then progressively worsening skew towards the end of the page.  I brought the replacement unit to service center for inspection, and HP decided to replace it with another new replacement unit. The second replacement unit came with the SAME ADF scan progressive skewing problem.

Attached is a sample of original print (in red) superimposed with the scanned skew image (in black). I read some where that a 2.5mm skew is normal. I cannot accept that.

Please help me to solve this problem. 

Thank you.

[Valsimot]

I under 2,5 mm skew is possible on entry-level printers for home and office use.

[Chee1]

Thanks for speedy reply. What do you think is the possible problem here ?

My guess is the ADF paper roller is not balanced , and when paper rolls off the paper guide it starts to skew. Because at start while within guide scan is straight

[Chee1 · Accepted solution]

I have finally decided to relief this HP M236sdw of its service.

I have replace it with Brother L2640dw at cheaper price tag, and the ADF scan produces a very nice image with very minimal skew towards the end of the page.

I am very disappointed with HP quality.