How to reset Canon S900 printer?

Try following reset procedure:

1. Turn off printer.
2. retaining button Resume/Cancel press button POWER - indicator it will catch fire by green color.
3. let go button Resume/Cancel, continuing to retain POWER.
4. press button Resume/Cancel of 2 times, retaining POWER, after which let go all buttons.
5. when indicator will be lit BY GREEN - press button Resume/Cancel of 4 times!!!
6. turn off printer by button POWER.

If reset does not work, you have to take apart the printer and empty the ink tank located at the back bottom right corner of your printer, replacing the sponge inside.

Here is an alternative procedure

1) With the printer power turned off, while pressing the Resume/Cancelbutton, press and hold the Power button. (DO NOT release the buttons.The LED lights in
green to indicate that a function is selectable.)
2) While holding the Power button, release the Resume/Cancel button. (DO NOT release the Power button.)
3)While holding the Power button, press the Resume/Cancel button 2 times,and then release both the Power and Resume/Cancel buttons. (Each timethe
Resume/Cancel button is pressed, the LED lights alternately in orange and green, starting with orange.)
4) When the LED lights in green, press the Resume/Cancel button 4 times (Each time
the Resume/Cancel button is pressed, the LED lights alternately in orange and green, starting with orange.)
5)After the function (menu) is selected, press the Power button. The LEDlights in green, and the selected function is performed. (When theoperation completes,
the printer returns to the menu selection mode automatically.)

You find reset procedure here.

Here is also a reset software, http://rm1.biz/resetprinter .

To reset the ink absorber is almost full:

1. Remove print head by following manufacturer procedure (available at www.canon.usa.com.
2. Turn off printer.
3. While pressing the Resume/Cancel button, press and hold the Power button. (Do not release the buttons. The Power LED lights in green to indicate that a function is selectable.)
4. While holding the Power button, release the Resume/Cancel button. (Do not release the Power button.)
5. While holding the Power button, press the Resume/Cancel button 2 times. Then release both the Power and Resume/Control button.
6. When the Power LED lights in green, press the Resume/Cancel button 4 times.
7. Turn printer off. Then replace the printer head using manufacturer's procedure available on line.
8. The printer is now reset and you are ready to print.

Larry