HP4000 printing blank pages (SOLVED)

[dsc3507]

This is not a request for help but rather a message that this was solved.

My  printer was printing blank pages and the left top lid cover hinge had broken. I did not realize that this opened the laser shutter until I read about it on here in another topic. So I downloaded the HP4000 service manual - google HP4000 service manual - and dismantled the printer right side and top cover. I removed all the broken pieces and located the shutter which is at the top of the black laser assembly. It is spring loaded. Suggestions I saw were to use a pencil eraser to hold it open. I thought that was a potential problem way to do it as the eraser could come dislodged and  jam somewhere. Instead I used a material called coax seal which is a malleable substance not unlike clay used to seal RF connectors. I pushed the shutter open and applied a liberal amount of the material so it could not close. I did this on both sides to be safe. I suppose the shutter could just be removed but I did not want to take a chance of damaging something doing that. In the end the printer prints fine with a new old stock 27A cartridge.  The printer has printed 36400 pages which I guess is low for its age. It is a home network printer and has worked great for years.

[Repairatrooper]

Please keep in mind that by disabling the safety interlock there exists the possibility of optical exposure to the laser which is why the interlock exists. 

[dsc3507]

This is not the reason for the shutter. The laser would never be viewd unless you could get your head into the printer and I doubt that. The reason for the shutter is to avoid contamination from the toner cartridsge when you install and remove it. Since this is very unlikely keeping it open is not a problem. The shutter was an overkill precaution by HP.