If you can, scan and post a small crop of a sample print showing exactly how it's blurry.
On our IRC3200, a number of times we got toner under the transfer belt and this caused the colors to lose registration with eachother so C M and Y were offset by a fraction of an inch. Under service contract, we had the ITB belt replaced when this happened if it already had 150k or more on it, but once the tech simply cleaned it and it was fine again after that for some time so I've done that a number of times too. In some instances it was very noticeable right away - other times it was a bit more subtle. I created a test print with C M Y and K short lines that were placed end to end so I could see exactly how the color to color registration was when I suspected the print didn't look quite right and this was useful for quickly identifying when it was necessary to clean the backside of the transfer belt.
With the cleaning blade, we usually just got toner smudges and residual toner that should have been cleaned off.
Post a picture and maybe it will look familiar exactly what you're seeing.
