HP PSC 2510 Clean Scanner Glass

If your printer is making a clicking noise or grinding noise, then cleaning the underside of the scanner glass is a good solution. HP PSC all-in-one printers that have the same scanner assembly are prone to exhibiting this fault. As soon as the printer switches ON, it begins a continuous grinding clicking noise. The display usually shows an hourglass or sometimes instructions for cartridge alignment which never completes successfully. The power light may also flash during this time.

The scanner bed detects its home position at the edge, by detecting a white strip. The detection of this strip signals the microcontroller to stop the motor from turning further. Obviously if the sensor does not detect the white strip, the motor continues turning even when it has reached the end, hence the clicking sound. This is actually a very ingenious method of detecting the edge, without using any additional sensors such as micro switches, which also keeps the cost of the printer low.

Microscopic molecules of ink escape into the air and settle around the underside of the scanner glass. Over time the reflectivity of the white strip changes as more ink molecules settle on it. They also settle in the scanner assembly, which consists of mirrored strips of glass and a fluorescent light source. The finely calibrated electronics expects to receive a specific threshold value of reflected light, and when it does not receive this amount, the microcontroller assumes the scanner bed has not reached the end, and it continues powering the motor. Luckily, the cogwheel assembly jumps when turning past the limit and that is the clicking and grinding noise that everyone hears.

Cleaning Glass along the White Strip

As you can see, removing the scanner glass to clean it from the underside usually helps. When I first opened this, I was looking for a micro switch, which would signal the home position of the scanner bed, but quickly came to realise that they are using the scanner sensor itself to detect the edge.

White Strip

The white strip appears fine to the naked eye, and one would not suspect any ink, but there is a very fine layer of inkjet residue on the glass.

Removing the Ink Residue

I used an appropriate professional cleaner and some kitchen tissue to remove the small particles of ink residue on the strip. It was surprising to see the amount of ink that had settled after all the years of use. Simply clean the strip and re-assemble the printer again and it should work. When assembling it, make sure that the scanner bed is in the home position where it is supposed to be when the printer starts.

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