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HP Laserjet 4 Image problems with large black areas
Hi,
I used to use a HP LJ4 for prototyping PCBs, but ive recently come back to electronics after a long break and now the printer has a weird fault. Self-test works fine, but in PCB artworks an afterimage at 94mm can be seen, as well as horizontal banding in the black areas, the banding seems to be related to the amount of black on that line (more black=lighter black). Im told the afterimage is a sign the photosensitive roller is on its way out, but Ive just put a spare toner assembley in it and its doing the same thing with the replacement toner. While im not dismissing the idea that the spare toner could have the same fault, im dubious its a toner issue (and am a little unwilling to fork out £100 for a toner cartridge to find out!) Any ideas on what else it could be? My best guess on the banding would be a worn out capacitor somewhere in the power supply to something, and the after-image may be related to something like a roller not getting power (eg the roller that neutralises the old image on the drum before the new image is constructed), but im not ruling out a toner cartridge problem - the spare came with the printer and was unused (toner tab intact) but not in a black bag and handling has been suspect (stored on its side for a while), so its possible the cartridge is broken, but I dont buy it being broken in exactly the same way as the other cartridge, and would probably look elsewhere. Can anyone shed any light on this? TIA for any help. |
AlanH wrote:
I used to use a HP LJ4 for prototyping PCBs, but ive recently come back to electronics after a long break and now the printer has a weird fault. You might ask in comp.periphs.printers or see http://www.fixyourownprinter.com/ or http://www.printerworks.com/ . Standard disclaimers apply; I don't get money from any of the companies mentioned. Matt Roberds |
"AlanH" wrote in message ... Hi, I used to use a HP LJ4 for prototyping PCBs, but ive recently come back to electronics after a long break and now the printer has a weird fault. Self-test works fine, but in PCB artworks an afterimage at 94mm can be seen, as well as horizontal banding in the black areas, the banding seems to be related to the amount of black on that line (more black=lighter black). Im told the afterimage is a sign the photosensitive roller is on its way out, but Ive just put a spare toner assembley in it and its doing the same thing with the replacement toner. While im not dismissing the idea that the spare toner could have the same fault, im dubious its a toner issue (and am a little unwilling to fork out £100 for a toner cartridge to find out!) Any ideas on what else it could be? My best guess on the banding would be a worn out capacitor somewhere in the power supply to something, and the after-image may be related to something like a roller not getting power (eg the roller that neutralises the old image on the drum before the new image is constructed), but im not ruling out a toner cartridge problem - the spare came with the printer and was unused (toner tab intact) but not in a black bag and handling has been suspect (stored on its side for a while), so its possible the cartridge is broken, but I dont buy it being broken in exactly the same way as the other cartridge, and would probably look elsewhere. Can anyone shed any light on this? TIA for any help. If 94mm is the circumference of the fuser roller then suspect the fuser temp or contaminated fuser or broken fuser roller PTFE surface. Copier & laser printer tips http://www.divdev.fsnet.co.uk/copiers.htm -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
On Wed, 31 Aug 2005 02:24:09 GMT, AlanH
wrote: Hi, I used to use a HP LJ4 for prototyping PCBs, but ive recently come back to electronics after a long break and now the printer has a weird fault. Self-test works fine, but in PCB artworks an afterimage at 94mm can be seen, as well as horizontal banding in the black areas, the banding seems to be related to the amount of black on that line (more black=lighter black). Im told the afterimage is a sign the photosensitive roller is on its way out, but Ive just put a spare toner assembley in it and its doing the same thing with the replacement toner. While im not dismissing the idea that the spare toner could have the same fault, im dubious its a toner issue (and am a little unwilling to fork out £100 for a toner cartridge to find out!) Any ideas on what else it could be? My best guess on the banding would be a worn out capacitor somewhere in the power supply to something, and the after-image may be related to something like a roller not getting power (eg the roller that neutralises the old image on the drum before the new image is constructed), but im not ruling out a toner cartridge problem - the spare came with the printer and was unused (toner tab intact) but not in a black bag and handling has been suspect (stored on its side for a while), so its possible the cartridge is broken, but I dont buy it being broken in exactly the same way as the other cartridge, and would probably look elsewhere. Can anyone shed any light on this? TIA for any help. I have posted the Laserjet 4,5 (M,N,Plus) combined service manual on one of my websites just for you. It's in PDF format. With any luck, this 453 page manual will help... Failing that, clean the corona wire. See: http://web.newsguy.com/MichaelGray/ |
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