dplatt@coherent.com (Dave Platt) (08/05/89)
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manual for the DeskJet family says that it can be caused by problems with the cartridge itself (running out of ink; outdated; needs re-priming; defective) or in the interface between the printer's driver-electronics and the cartridge itself (cartridge not inserted securely; dirty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. -- Dave Platt FIDONET: Dave Platt on 1:204/444 VOICE: (415) 493-8805 UUCP: ...!{ames,sun,uunet}!coherent!dplatt DOMAIN: dplatt@coherent.com INTERNET: coherent!dplatt@ames.arpa, ...@uunet.uu.net USNAIL: Coherent Thought Inc. 3350 West Bayshore #205 Palo Alto CA 94303
rickk@hpvcfs1.HP.COM (Rick Klaus) (08/07/89)
Well, I wouldn't say NO internal fonts... The DeskWriter has a very low quality internal font for just the purpose which you describe. It will only show up when the self test is printed or an error message needs to be printed. It should NOT be used as a sample of what DW printouts look like. To activate the self test, hold down the Select key while turning the printer on. You will get the same nozzle pattern and list of defective dots which were described by Dave Platt. See Ya at MacWorld!! Stop by for a DeskWriter Demo! Rick Klaus hplabs!hpvcfs1!rickk