Printer - double-sheet pickup issue

Question

I have a Canon I-SENSYS MF232w printer. This problem started 2 days ago. I want to print one page. It prints my page, but it takes 2 papers with correct paper. What causes that?

EDIT: This happens when I print from PC. But copier works properly.

Answer 1

I'm gonna add this as a second answer, because I used to be a professional paper-handler [yup, weird job, I worked in a print shop/bindery at the time]

I don't necessarily think this will be the primary cause - I think the commented suggestion of cleaning all the rollers with isopropyl alcohol is the most likely - but it's amazing how many people don't know this simple trick to align & free up a stack of paper.

Getting air between sheets of paper - ie, entire stack separation in one move - is a simple skill, but not one that people naturally seem to figure out for themselves.
The entire thing takes far less time to do than to describe - it's a 5 second job.

1. Start with your ream of paper on a table which is against a wall or other suitable vertical surface - a corner is even better.

2. Turn the ream so the long edge is facing you.

3. Hold the entire ream by the two nearest corners & without applying any grip pressure, bend the corners up, so you generate a curve across the entire front edge of your ream.

4. Whilst bent, then grip the corners firmly & 'unbend' the ream back to flat.

5. This 'lift & pull' will generate an even gap between every single sheet in your stack. The 'slap' will push that air evenly through the entire surface of each sheet.
   In one smooth movement, lift the entire ream & pull the corners back out to full width as you do it - whilst attempting to keep it flat as it rises [in practice you kind of achieve this on the way back down if the paper is large, but for A4 or A3 it's really just a wrist flick rather than a full lift] then slap it flat onto your table. You only need to lift a couple of inches, unless your paper is A0 or bigger ;)
   You can do this a couple of times, if you didn't quite get it the first time.

6. Push the ream against your corner or vertical back-surface. Let go the corner pressure but don't let go of the ream, as at this point it will pour off the table like a liquid. Keep your fingers so that you have the corners 'captured' but you're not holding, just guiding.

7. Now you can very easily jog the ream against your wall or into your corner.

8. Making sure it doesn't move, then you need to press down on the top to knock all that 'spare air' back out again.

Done.
Now you have re-aired the entire stack & you can put it back into your paper feed.
If that doesn't fix it, separation wasn't the problem.

After the late question edit it feels more like a software/config error, but I'll leave this answer here for all you budding paper-handlers out there ;-)

Answer 2

Maybe the papers got some moisture. Try to separate the sheets manually then return them to the sheets feeder.