Tom

asked Sep 4, 2001 at 4:09pm
Hp HP LaserJet 4

HP4+ poor print quality

I have a hp4+ with an under 10k page count.

In the midst of a 200 page print job the print quality went from normal density to what I would describe as gray scale. As I have another hp4 in the office I switched the toner cartridges with no effect. There are no other abnormalities on the pages and the print is fused. I printed a test page from both the printer control panel and from the computer software with the same results. There are no error messages being displayed.

Any ideas?
According to my HP IV bible any faint print condition could be caused by:

Toner (ya tried that)
Print density adjustment
Paper finish
defective transfer roller
or low laser power

I suggest you try reseating or replacing the transfer roller.
by unknown on Sep 4, 2001 at 4:52pm Add comment
It might have somehow went to econo mode.
Check the test print and see if econo mode is set to on. If it is, go to the menu that it's listed under and turn it off.
by moe on Sep 4, 2001 at 7:09pm Add comment
Thanks for the responses:
Would/could the transfer roller cause the print to change that dramatically from one page to the next?
It is not in econo mode.
How do I check for low laser power?
by Tom on Sep 5, 2001 at 11:43am Add comment
First thing to try is cleaning the high voltage power supply, it looks like a black box above the paper tray with the printer on it's side with the paper tray removed. There's a good chance that dirt/toner has migrated into that area and it can cause your problem, the transfer roller degrades slowly, you don't notice it as quickly as your saying .
by Andy on Sep 5, 2001 at 2:07pm Add comment
Since you have another laser printer in the office, try swapping the transfer rollers. They pop out easy enough. Only handle them by the metal shafts. You can't adjust the laser power. The high voltage units are pretty easy to remove, 2 screws and they pop off. You can try swapping those if the other thing don't work. The scanner assy wouldn't go bad that quickly. It takes time for dust to accumulate on the optics and I've never seen the power level change suddenly.
by moe on Sep 5, 2001 at 5:26pm Add comment
Hello Tom!

Sikna asks:

Is this problem permanent now?

If so the laser unit may have gone bad...

Or could be engine controller board.

Sikna out...
by unknown on Sep 5, 2001 at 6:10pm Add comment