My Canon Pixma is not printing properly. Sometimes it prints sometimes it doesn't. Any info and help appreciated.

First, are you running low on those ink colors? If not, possibly print cartridges need cleaning. If printer has separate print heads, they made need cleaning.
Lastly, print head(s) may need replacement.

Hy, this is a clasic case. you need to replace the printhead. I know this sounds drastic but this is the only way. BTW, I service and sell Canon products and have seen this many times.

the magenta print head must be blocked. have it checked canon pixma ink

That's as common as rocks with inkjets, especially if Copy doesn't produce visible output. Fortunately the clean cycle gets results pretty often. You need to heed the printer humidity spec. and follow the manual's further actions for when 'Clean Head' doesn't work (typically cleaning its bedding and/or running some rubbing alcohol through via a handy empty cartridge.) See your local ink refiller if you want a friend to lean on for cleaning cartridge fiddling.

Hello,
try to do deep head cleaning, few times. If this doesn't helps you need to remove the ink's and print head and bottom of print head ( where are ink nozzles ) few times press on wet cloath.

Then repeat the deep cleaning.

Suggest you download the On-Screen Manual and refer to the Troubleshooting Section:

http://www.usa.canon.com/cusa/support/consumer/printers_multifunction/pixma_ip_series/pixma_ip1800#BrochuresAndManuals

Sounds like you have anumbe rof problems; I would suggest you check to make all parts are properly installed and you perform a cleaning.

Trust this is helpful.

Try dis-connecting all cables from printer, then re-connect them all back.

It sounds like you have a faulty black cartridge. Have you tried a OEM cartridge? Sometimes aftermarket/refilled cartridge inks are not up to specs and gum up the nozzles. It sounds like the problem you are having.

1: check in the printer properties( page setup ) is it latter then make it A4
2: clean the roller
3: also when u printting check with uper try not from try 2
if its printing proper then try is touching roller

If deep cleansing via software doesn't work then you've got to manually clean your print head unit. Sometimes you'll have to bite the bullet and get a replacement print-head unit ($$). If you're at the stage that you're considering replacement, then you've got nothing to lose by cleaning the print-head unit yourself. It's simple. Remove all ink cartridges first then remove the print head itself. Place the print head unit in a saucepan of warm (NOT boiling hot) water and leave to soak for an hour. (Protect your clothes - it gets messy) After an hour, flush the printhead unit under a running tap. Don't run the water too fast or you may damage the unit) You should flush until the water runs clear. Do not attempt to clear the nozzles with anything other than water - they are very fine needle jets and you will damage them!! If needs be, return to saucepan and leave to soak in warm water again and repeat process. When you are satisfied that the printhead is clean, you need to dry the unit thoroughly. Shake as much water from it as you can then pat it gently dry. Next place it on some absorbant kitchen paper and put the unit in a warm place to thoroughly dry (Overnight in a warm airing cupboard would be good). Once dry, refit the unit put in (Preferably new - but I've used existing one's without problem) cartridges and run a cleaning cycle. Your printer should now work as if new!!! - In Most cases!! - sometimes though, you'll either have to replace the print head unit - which sometimes can be more expensive that simply replacing the printer. What have you got to lose though eh? CLIVUSS