More out of interest what went wrong than necessity as only used for poster
use. Epson Stylus 915, if relevant.
Lack of Red and excess of Yellow
A perfectly adequate get-around is +30 percent of Red and 30 percent less
each of Green and Blue in the graphics package. It all started with a postal
packing foam "doughnut" dropping unnoticed into
the paper entry slot and numerous paper jams before finding the culprit. The
ink-jet cartridges are re-set , re-used/ redilled multiple times and
refilled and reset since this foam business. Built-in "cleaning" and the
other maintainence routine has made no difference. The colour imbalance is
stable and invariant over perhaps 30 sheets and 4 separated sessions.

N_Cook wrote:

More out of interest what went wrong than necessity as only used for poster
use. Epson Stylus 915, if relevant.
Lack of Red and excess of Yellow
A perfectly adequate get-around is +30 percent of Red and 30 percent less
each of Green and Blue in the graphics package. It all started with a postal
packing foam "doughnut" dropping unnoticed into
the paper entry slot and numerous paper jams before finding the culprit. The
ink-jet cartridges are re-set , re-used/ redilled multiple times and
refilled and reset since this foam business. Built-in "cleaning" and the
other maintainence routine has made no difference. The colour imbalance is
stable and invariant over perhaps 30 sheets and 4 separated sessions.

At a guess, there's some crud on top of a colour-calibration photodiode
somewhere inside.

Cheers

Phil Hobbs

Phil Hobbs wrote in message
...
N_Cook wrote:

More out of interest what went wrong than necessity as only used for
poster
use. Epson Stylus 915, if relevant.
Lack of Red and excess of Yellow
A perfectly adequate get-around is +30 percent of Red and 30 percent
less
each of Green and Blue in the graphics package. It all started with a
postal
packing foam "doughnut" dropping unnoticed into
the paper entry slot and numerous paper jams before finding the culprit.
The
ink-jet cartridges are re-set , re-used/ redilled multiple times and
refilled and reset since this foam business. Built-in "cleaning" and the
other maintainence routine has made no difference. The colour imbalance
is
stable and invariant over perhaps 30 sheets and 4 separated sessions.

At a guess, there's some crud on top of a colour-calibration photodiode
somewhere inside.

Cheers

Phil Hobbs


Is that part of the printer hardware? like the auto-exposure photodiode
inside a photocopier? ie not in the ink-jet carts.
Time to explore the innards of one of those junkers in the mule-park, I
think, to get the hang of ink-jet general operation.

N_Cook wrote:

Phil Hobbs wrote in message
...
N_Cook wrote:

More out of interest what went wrong than necessity as only used for
poster
use. Epson Stylus 915, if relevant.
Lack of Red and excess of Yellow
A perfectly adequate get-around is +30 percent of Red and 30 percent
less
each of Green and Blue in the graphics package. It all started with a
postal
packing foam "doughnut" dropping unnoticed into
the paper entry slot and numerous paper jams before finding the culprit.
The
ink-jet cartridges are re-set , re-used/ redilled multiple times and
refilled and reset since this foam business. Built-in "cleaning" and the
other maintainence routine has made no difference. The colour imbalance
is
stable and invariant over perhaps 30 sheets and 4 separated sessions.

At a guess, there's some crud on top of a colour-calibration photodiode
somewhere inside.

Cheers

Phil Hobbs

Is that part of the printer hardware? like the auto-exposure photodiode
inside a photocopier? ie not in the ink-jet carts.
Time to explore the innards of one of those junkers in the mule-park, I
think, to get the hang of ink-jet general operation.

not-a-printer-guy warning

I'm not sure if the printer does self-calibration, but if it does, the
cal PDs will be part of the hardware. It doesn't sound like a nozzle
problem, since it doesn't get worse, and the self-clean feature doesn't
change it. It doesn't sound like a contact problem, because changing
the cartridges doesn't change it. So I'm just guessing that there is
some internal calibration being done, and that one of the PDs is dirty,
which would move the calibration point in a nice repeatable way as
you're seeing.

/not-a-printer-guy-warning

Cheers

Phil Hobbs

On Wed, 12 Sep 2012 08:32:00 +0100, "N_Cook"
wrote:

More out of interest what went wrong than necessity as only used for poster
use. Epson Stylus 915, if relevant.

That would perhaps be an Epson Stylus Color 915 or an Epson Photo
Stylus 915? They're quite different printers.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Wed, 12 Sep 2012 09:02:40 -0400, Phil Hobbs
wrote:

At a guess, there's some crud on top of a colour-calibration photodiode
somewhere inside.
Phil Hobbs

That's not quite what happens when there's crud blocking the photo
diode. When some of the light is blocked to the photo diode, the
mechanism thinks that the printer is printing too lightly, and
compensates by applying more ink to the paper (making a drippy mess).
If the paper looks like there's far too much ink being applied, it's
probably a clogged photo diode.

The only the time there's a change in color balance is when the print
calibration routine is run. It first prints a test page with
psychedelic patterns, colorful stripes, and bizarre blotches. It then
scans the printing with the photo diode and eventually compensates for
any color alignment (convergence) and balance errors. Between
calibration runs and print cartridge changes, it stores the settings
in NVRAM.

However, a 30% difference in color balance is more than what I believe
the printer can normally compensate. Something else is wrong. I'll
wait until the correct model number is disclosed so I don't waste time
on the wrong printer.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote in message
...
On Wed, 12 Sep 2012 08:32:00 +0100, "N_Cook"
wrote:

More out of interest what went wrong than necessity as only used for
poster
use. Epson Stylus 915, if relevant.

That would perhaps be an Epson Stylus Color 915 or an Epson Photo
Stylus 915? They're quite different printers.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

says Epson Stylus Photo 915 on the front

On Thu, 13 Sep 2012 08:08:20 +0100, "N_Cook"
wrote:

Jeff Liebermann wrote in message
.. .
On Wed, 12 Sep 2012 08:32:00 +0100, "N_Cook"
wrote:

More out of interest what went wrong than necessity as only used for
poster
use. Epson Stylus 915, if relevant.

That would perhaps be an Epson Stylus Color 915 or an Epson Photo
Stylus 915? They're quite different printers.

says Epson Stylus Photo 915 on the front

I can't find any specific documentation on sensor cleaning online.
I'll be visiting the local authorized Espson repair station next week
and will try to extract some info from them.

Meanwhile, I've seen color balance problems change when printing on
different computers. One computer prints fine, while the others print
strange colors. I eventually traced it back a trashed color profile
file (*.ICC). Try downloading a new file and try again.
http://esupport.epson-europe.com/FileDetails.aspx?lng=en-GB&data=FGQ8MBMpKlvlhkjV5Z0NdBnf1pcygH1g&id=3507

You can also get some weird colors if you select the wrong type of
paper, but not 30% error. Check the paper type anyway.

Check the waste ink pad. If it's saturated with ink (or dripping ink
out the bottom of the printer), it should be replaced. When
saturated, it tends to slop ink all over the print heads, resulting in
a "dirty" looking color print. If all your colors look like a little
black is mixed in, that's your problem.

If you don't think it's the computah, you can run a test pattern from
the front panel and remove the computah from the equation:
http://esupport.epson-europe.com/ViewArticle.aspx?lng=en-GB&kbid=313620
Do the colors look normal without a computah involved?

Also, check the head alignment utility again:
http://esupport.epson-europe.com/ViewArticle.aspx?lng=en-GB&kbid=311800

If you're really desperate, there's the Epson service utility:
http://inkjetprinterhelp.us/epsonSSC.html
which can be used to tweak the carts. However the Stylus Photo 915 is
not listed as a supported printer, so you may have problems using it.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Phil Hobbs wrote in message
...
N_Cook wrote:

More out of interest what went wrong than necessity as only used for
poster
use. Epson Stylus 915, if relevant.
Lack of Red and excess of Yellow
A perfectly adequate get-around is +30 percent of Red and 30 percent
less
each of Green and Blue in the graphics package. It all started with a
postal
packing foam "doughnut" dropping unnoticed into
the paper entry slot and numerous paper jams before finding the culprit.
The
ink-jet cartridges are re-set , re-used/ redilled multiple times and
refilled and reset since this foam business. Built-in "cleaning" and the
other maintainence routine has made no difference. The colour imbalance
is
stable and invariant over perhaps 30 sheets and 4 separated sessions.

At a guess, there's some crud on top of a colour-calibration photodiode
somewhere inside.

Cheers

Phil Hobbs

I worked out how to get to the active jet face.
remove both carts and unclip their top clamps
Remove the ribbon shield, hidden plastic tang and nib at the rear
Undo the 2 obvious screws
lift the subassembly away from the carrier, slight joggling required
no obvious opto device underneath

Cleaned the active face with alcohol and replaced , but no change in colour
balance
At least I've not made it worse (if it ain't broke, don't poke)

Perhaps its an unintended consequence of doing resets, something stored
erroneously somewhere