Print head is in, yet message reads to install print head....canon i900d

SOURCE: error message on canon i900D

1. Underneath the printer, look for the triangular arrow on the AC Adapter, which points to a detent. Fully depress the detent, remove the AC Adapter and unplug it. Align the cable so that it will pass through the hole in the case when you remove the printer assembly.
2. Open the front cover to the vertical position and tug it at the hinge points to remove it.
3. The black, card-slot cover has two holes marked by triangles. Remove the two Phillips head screws, being careful not to lose them in the printer mechanism. Coax up card slot cover with a dull knife or similar tool and remove it.
4. On the top left of the printer, notice the triangle point at a slot. Insert a screwdriver or similar tool into the slot and depress the detent. Ease the little cover over the USB cable connector towards the rear of the printer and remove it.
5. Remove the “Operation Panel and Window Display” (OPWD). Lift the window display to the horizontal position and remove the two Phillips head screws. Rotate the OPWD forward and out the two hinges at the bottom. Lower the tiny snap that holds the OPWD strap cable and remove the OPWD.
6. Note the slot marked with a triangle between the two OPWD hinge slots. This is one of the six slots, all marked with a triangle, which access the detents that hold the upper casing. Locate the other five. One is on the left-side front of the printer in the same relative position as the one hidden under the OPWD. The other four are in the rear of the printer. Depress these detents in turn, working around the printer, and coax up the upper casing. This requires fortitude, patience and one or more dull, thin instruments.
7. On the right side of the printer, remove the Phillips head screw that fastens the yellow wire to the chassis of the printer.
8. Disconnect the connector on the Digital Camera Connector (DCC) circuit board and ease the cable out of the printer casing as far as you can. (I feared damaging the connector and removed the circuit board and DCC cover instead.) This cable is hooked at the right hand rear corner of the printer casing.
9. Looking down on the printer mechanism, locate the two Philips head screws near the rear. These fasten the printer to the base. Remove them carefully.
10. Placing a hand under the paper feed barrel, lift the printer assembly up and rest it on the case while you fight the DCC cable off the hook at the right rear corner. Once you free it, remove the printer assembly and congratulate yourself.
11. Wearing disposable gloves, remove the five ink absorbent pads and rinse them under the facet in the laundry sink. Cold water is fine. Press the pads with your fingers until the water runs clear. Do not wring or otherwise torment the pads, as you want them to retain their shape. Press the pads between old newspapers to squeeze out most of the moisture. Expect to be surprised at the amount of liquid these felt pads can hold. I dried mine in the sun. Use a hair dryer, clothes dryer, microwave or oven at your own risk.
12. Reassemble the printer in the reverse order of disassembly.
12.1. Insert the small absorbent pads first. The right side pad with the green facing goes on top. (I think.)
12.2. Caution: Before replacing the upper casing, note the small electrical gismo on the left side of the printer assembly. It has a slot that fits into the plastic wheel. When properly positioned, the gismo snaps into place. Make sure the gismo is correctly seated before replacing the upper casing.

SOURCE: I get "Print head not installed on my canon i900d

Reseat the print head i900D and reset the printer.Turn it off ,wait 10 sec then turn it on.