"I have an HP ThinkJet 2225C printer. I just replaced the print cartridge. It still doesn't print dark enough, and even after I primed the cartridge a few times, it still also misses a dot at the top and the second one from the bottom.
I'm wondering, could the voltage to the cartridge be too low?"
I have seen on rare occaisions the cartridge bad out of the box! Try wiping down the cartridge head & contact points on the printer with a Q-tip & alcohol. Sometimes blowing in the vent holes will force ink out the head, wipe off excess and try it. You may have to repeat the procedure a few times. If this doesn't work get another cartridge. You may want to try swopping the bad cartridge into a working unit or taking a working cartridge and putting it in the suspect printer.
(From: Frank Reid (firstname.lastname@example.org).)
I agree with all Kevin said. I use blue window-cleaner (e.g. Windex) instead of alcohol; the ink is very soluble in that stuff, and it penetrates the tiny holes in the printhead. After cleaning, hold a rag over the printhead and sling it downward a few times (as if throwing, but don't let go), such that centrifugal force pushes some ink out. If that doesn't work, try blowing on the upper vent.
On a few rare occasions I've encountered bad connections at the fixed end of the printhead cable, fixed by reseating the connectors. Also, if the cartridge has leaked, there may be ink on the gold pads in the moving end of the printhead connector, causing bad contact. Clean as above.
Some of the later models, including the type which takes two cartridges (3-color and black), have screws at the end of the carriage rod which allow adjusting the clearance between printhead and paper. Those may need adjusting if the ink is smearing. If too light, it's probably a printhead problem.
(From: Richard M. (Digitech@bogus.net).)
It is a water based ink. There is no need for any solvent other than water. Warm water works well. Use it all the time on my 1200C and DJ750C... BTW, I never have to touch my Epson. Use lint free cloths to tamp dry. NEVER wipe.
(From: R. Wagner (email@example.com).)
I found the cable from the computer to the print head had some open places close to the head. The want 35 dollars for a new one. I went to the auto parts store and got some a rear window defroster repare kit. I got it working but for how long I dont know.