LaserJet 1100 - excessively high contrast

[CR Optiker]

I described my problem in a post on 13Jan07 entitled "Laserjet 1100 - drum
wearing out?" I'm starting a new thread because though various posts and
some testing, I think a fresh look is justified.

From previous posts, the toner drum is integral to the toner cartridge,
however, the fuser drum is not, and past problems with toner not sticking
suggests a bad fuser drum as a possibility.

I DLed and installed the latest (2002 if I recall) driver for this printer,
and that improved the print quality significantly, but it is still far from
acceptable. I am printing in the highest quality setting, but also tried in
the Economode setting,but it was entirely unacceptable as it printed the
text characters as outlined, but not filled.

The symptoms are that the contrast of prints is very, very high resulting
in washed out images. The contrast of text is also much more than in
previous prints of the same document. The document contains normal-italic
and non-italic bold text in the same size and font. The normal-italic is
comparable in old and new prints, the non-italic-bold is much, much bolder
in teh new than the old print - almost as if it was an extra-bold setting.

I have tested a PDF verison of the document, and have also tested by
printing one of the grayscale images alone - not imbedded in the MS Word
document - by opening it and printing from IrfanView. It has he same overly
high contrast as the Word document of the page containing that image.

Can anybody think of what may be causing abnormally high contrast?

Any suggestions appreciated.

Thanks!
Optiker

 

[ato_zee]

Can anybody think of what may be causing abnormally high contrast?

http://www.eserviceinfo.com/
Has the free service manual just enter 1100 in search, and hp in mfr.
Some early HP printers had a contrast dial, maybe they put it
inside as a preset, the manual will show what adjustments there
are. Mark presets with their position before you move them,
then you can get back to where you started. In general
don't move presets too far from their original setting, circuits
can be damaged, laser diodes can be over-run, TV's can
blow their LOPT with excessive scan amplitude, etc.
Fusers are commonly heated with a linear quartz halogen.
Temperature set by a thermistor driven control circuit, there
may be a preset to adjust the temperature, and cover
component tolerances.

 

[CR Optiker]

http://www.eserviceinfo.com/
Has the free service manual just enter 1100 in search, and hp in mfr.
Some early HP printers had a contrast dial, maybe they put it
inside as a preset, the manual will show what adjustments there
are. Mark presets with their position before you move them,
then you can get back to where you started. In general
don't move presets too far from their original setting, circuits
can be damaged, laser diodes can be over-run, TV's can
blow their LOPT with excessive scan amplitude, etc.
Fusers are commonly heated with a linear quartz halogen.
Temperature set by a thermistor driven control circuit, there
may be a preset to adjust the temperature, and cover
component tolerances.

ato...Thanks for the reply.

I probably failed to mention it, but I've had no problem with the printer
doing anything like this in the past. I haven't used it a lot laely for
anything that had a lot of grayscale graphics, so hard to say whether it
started abruptly or gradually. Also can't think of anything I've done that
might have changed it. I did install Linux dualbooted and had this printer
set up to print from Linux as wellas Windows, but can't imagine how that
might have affected it since in Linux, it was using an entirely different
driver.

Will take a look at the link and see what I might learn. As far as I know,
this printer has no adjustments of any sort - bottom end laser printer at
the tiem I bought it.

Optiker

 

[Tony]

I described my problem in a post on 13Jan07 entitled "Laserjet 1100 - drum
wearing out?" I'm starting a new thread because though various posts and
some testing, I think a fresh look is justified.

From previous posts, the toner drum is integral to the toner cartridge,
however, the fuser drum is not, and past problems with toner not sticking
suggests a bad fuser drum as a possibility.

I DLed and installed the latest (2002 if I recall) driver for this printer,
and that improved the print quality significantly, but it is still far from
acceptable. I am printing in the highest quality setting, but also tried in
the Economode setting,but it was entirely unacceptable as it printed the
text characters as outlined, but not filled.

The symptoms are that the contrast of prints is very, very high resulting
in washed out images. The contrast of text is also much more than in
previous prints of the same document. The document contains normal-italic
and non-italic bold text in the same size and font. The normal-italic is
comparable in old and new prints, the non-italic-bold is much, much bolder
in teh new than the old print - almost as if it was an extra-bold setting.

I have tested a PDF verison of the document, and have also tested by
printing one of the grayscale images alone - not imbedded in the MS Word
document - by opening it and printing from IrfanView. It has he same overly
high contrast as the Word document of the page containing that image.

Can anybody think of what may be causing abnormally high contrast?

Any suggestions appreciated.

Thanks!
Optiker

What does the internal test page look like, is that also washed out? (press the
button to execute an internal test print).
If the test print is the bad, try a half test. Print a page and when the
trailing edge of the paper is just about to disappear, open the door and stop
the printer. Remove the cartridge and examine the page, is the image is washed
out on the paper that you can see under where the cartridge was? If it is you
have an imaging problem, if it is not washed out but the portion of the page
that has been fused is washed out you have a fusing problem.
You can also perform an engine test. At the back of the printer, open the SIMM
door (hinges up), at the right side behind the SIMM slot there is a recessed
button. Push this with a non-metallic object. The printer should print a page
full of horizontal black lines. What do these look like, washed out or not?
Tony
MS MVP Printing/Imaging

 

[CR Optiker]

What does the internal test page look like, is that also washed out? (press the
button to execute an internal test print).
If the test print is the bad, try a half test. Print a page and when the
trailing edge of the paper is just about to disappear, open the door and stop
the printer. Remove the cartridge and examine the page, is the image is washed
out on the paper that you can see under where the cartridge was? If it is you
have an imaging problem, if it is not washed out but the portion of the page
that has been fused is washed out you have a fusing problem.
You can also perform an engine test. At the back of the printer, open the SIMM
door (hinges up), at the right side behind the SIMM slot there is a recessed
button. Push this with a non-metallic object. The printer should print a page
full of horizontal black lines. What do these look like, washed out or not?
Tony
MS MVP Printing/Imaging

Tony...

I can't tell from the test page, so I generated an image in GIMP that's a
square, filled margin to margin with a grayscale gradient, about 7" top to
bottom perpendicular to the gradient direction, centered vertically. I did
the half-test you suggested, pulled the cartridge and carefully extracted
the page. The area that hadn't yet been fused was a bit messed up, but
there was a clean area that had gone through the fuser and a clean area
that had un-fused toner, but not far enough through to get messed up when I
extracted the page. I don't subjectively see any difference in them, and
both show the full black to white gradient. The fused area seems well
adhered, and the unfused, of course, wipes off.

Visually, I would say that I can't detect any gradient in the black third -
the full grayscale seems to be compressed into the ligher two-thirds of the
page width. It's almost like a gamma problem. I'm an imaging scientist by
trade, so have a pretty good eye for image grayscale and features.

Qunatitatively...at 7X magnification, I can lo longer visually see the
dither pattern at a grayscale of about...

fused - 194
not-fused - 187

Of course, that assumes everything is linear, and I wouldn't count on it.

These are close enough to believe there's negligible difference. I can,
with the tools I have available at home, measure that gradient for each,
but am not sure that would be accurate because it would involve scanning
the gradient half-test page, then doing a smoothed profile using a digital
analysis tool. I know my system is not calibrated for all of that, so would
doubt the accuracy of results.

If you have any feel for what the resolvable grayscale level should be on
the black end, and if the numbers above are resonable (sasuming they are
even meaningful), or if this gives you any further ideas, I'd appreciate
your reply.

Thanks!
Optiker

 

[Tony]

Tony...

I can't tell from the test page, so I generated an image in GIMP that's a
square, filled margin to margin with a grayscale gradient, about 7" top to
bottom perpendicular to the gradient direction, centered vertically. I did
the half-test you suggested, pulled the cartridge and carefully extracted
the page. The area that hadn't yet been fused was a bit messed up, but
there was a clean area that had gone through the fuser and a clean area
that had un-fused toner, but not far enough through to get messed up when I
extracted the page. I don't subjectively see any difference in them, and
both show the full black to white gradient. The fused area seems well
adhered, and the unfused, of course, wipes off.

Visually, I would say that I can't detect any gradient in the black third -
the full grayscale seems to be compressed into the ligher two-thirds of the
page width. It's almost like a gamma problem. I'm an imaging scientist by
trade, so have a pretty good eye for image grayscale and features.

Qunatitatively...at 7X magnification, I can lo longer visually see the
dither pattern at a grayscale of about...

fused - 194
not-fused - 187

Of course, that assumes everything is linear, and I wouldn't count on it.

These are close enough to believe there's negligible difference. I can,
with the tools I have available at home, measure that gradient for each,
but am not sure that would be accurate because it would involve scanning
the gradient half-test page, then doing a smoothed profile using a digital
analysis tool. I know my system is not calibrated for all of that, so would
doubt the accuracy of results.

If you have any feel for what the resolvable grayscale level should be on
the black end, and if the numbers above are resonable (sasuming they are
even meaningful), or if this gives you any further ideas, I'd appreciate
your reply.

Thanks!
Optiker

Without seeing the output I am reluctant to draw any conclusions. I am also not
confident to comment on the gradient issue.
Did you try the engine test? That can sometimes show up any uneven printing.
The issue for me is to determine whether this is an engine problem or something
else. I have seen some weird problems with these printers caused by failing
laser scanners and main boards. In both cases there can be portions of the page
that are OK and parts that are not OK.
Tony
MS MVP Printing/Imaging

 

[CR Optiker]

Without seeing the output I am reluctant to draw any conclusions. I am also not
confident to comment on the gradient issue.
Did you try the engine test? That can sometimes show up any uneven printing.
The issue for me is to determine whether this is an engine problem or something
else. I have seen some weird problems with these printers caused by failing
laser scanners and main boards. In both cases there can be portions of the page
that are OK and parts that are not OK.
Tony
MS MVP Printing/Imaging

Tony...

No, haven't done the engine test yet. Will do tomorrow.

However, this is not a problem with a non-uniform page. Page uniformity
looks good. It's just that the contrast is so high that the blacks are very
black and the whites are very white, and I'm losing grayscale enough tht
parts of grayscale images that used to be visible in earlier rintings are
no longer there.

Will get back with results of engine test.

Thanks again!
Optiker

 

[Arthur Entlich]

I'm guessing a driver issue. Does the driver have any contrast or
lightness adjustments in it? You may wish to uninstall and reinstall
latest driver version.

Art