🚀 go-pugleaf

In article <420@mit-amt.MEDIA.MIT.EDU> mjkobb@media-lab.media.mit.edu (Michael J Kobb) writes:

> So, here's the question: Both times I've seen this engine demoed, (once
> on the DeskJet and once on the DeskWriter) I've noticed that one of
> the "scan" lines from the print head wasn't printing.  This results in
> REALLY thin white lines on large black fields, and in poor text
> rendition if it coincides with the top or bottom of any of the
> characters...  Is this a common problem?  If so, can it be easily
> corrected by somehow cleaning the head, or is a replacement necessary?

This is an occasional problem with this type of print-cartridge.  The
service manual for the DeskJet family says that it can be caused by
problems with the cartridge itself (running out of ink; outdated; needs
re-priming; defective) or in the interface between the printer's
driver-electronics and the cartridge itself (cartridge not inserted
securely; dirty contacts on the cartridge or in the printer).

The DeskJet and DeskJet Plus have a self-test feature (hold down FF or
FONT and press RESET);  it prints a test-page that includes a thin
diagonal line (which makes identifying clogged nozzles easier) and
listing the numbers of any nozzles whose inkjet resistors aren't drawing
the expected amount of current when fired (a _very_ elegant little
feature!).  I don't know whether the DeskWriter has retained any sort of
self-test feature, given that it has no built-in fonts with which to
print the information.

The printer service manual gives a whole set of tests that can be
performed to identify the cause of the missing dot.  A "shotgun"
approach would be:  remove the cartridge;  tap its side firmly on a
table-edge (breaking any bubbles in the injector nozzles);  clean the
copper contacts on the cartridge and in the printer carriage with a
cotton swab moistened with water (do _NOT_ attempt to clean the nozzles
on the cartridge!);  reinsert the cartridge, making sure it's fully
seated;  re-prime the cartridge.

If this procedure doesn't work, try a different (new) cartridge;  if
that one doesn't work, you almost certainly have a problem in the
printer itself.

For what it's worth:  I've had a DeskJet (original model) since last
November, have gone through 4 cartridges, and have had _no_ problems
with missing lines or with cartridges that clog or die before their ink
supply is exhausted.  

I've been told that some cartridges have been known to be "dead on
arrival", or to die prematurely, before they actually run out of ink.
If this should happen to you, take the cartridge back to your dealer;
I've been assured that HP dealers are authorized to accept DOA or
prematurely-dead cartridges for credit (perhaps on a pro-rated basis in
the case of cartridges that died prematurely?).

When buying DeskJet/DeskWriter cartridges, make sure that they're not
outdated.  The expiration date should be stamped on the cardboard box
(but isn't always present, I've found).  The manufacturing date is
stamped on the cartridge, in a coded form: XXYMMDDX (Y is the last digit
of the year, MM and DD are the month and date, and X represents a code
letter or digit not identified by the service manual).  Cartridges are
rated as having a shelf-life of 18 months when kept in the sealed
container, and 90 days when in the printer itself.

If you buy a cartridge and find that its expiration date has passed,
take it back to the dealer and complain.


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