My original response was a bit confusing.
Linda modified the housing unit to adjust the height. You will need that piece in order to get the silhouette to work properly. Once you have that, you can purchase replacement blades at any craft store. They can be any brand "Craft" blade.
I have the IX6520
The place you need to clean looks like
A bit of pressure won't hurt. Clean until the qtip stays clean.
The first time I did it, I went through about 100!
Then, turn off the power to the printer. Reset the cartridge so it's nice and straight. Turn on the power.
Hope it helps.
That sometimes happens to me when the connection points have a bit of ink on them. Use a qtip dipped in rubbing alcohol to gently clean the spot where the cartridge meets (on the printer not the cartridge).
I bet @icingimages can describe this better than I.
Imasri, this particular thread was from 2012. Luckily, Debbie is still with us. @icingimages. I have tagged her so she will know to come respond. The information from this thread may be outdated, and Debbie can tell us about the current products Icing Images offers.