For persistent bad printing -- clean the printer

Bad printing is sometimes due to a dirty printer. It is not the software at
all:


I just learned a simple and very obvious lesson about printing: eventually you
must clean the printer! Don't laugh. My printer dates from Kernel version 1.13,
that is 9 years ago. 

The task I describe here is: HOW TO Convince yourself the printer needs work.

The first symptom is "playing with your application print settings does not
help."

    The task is to test your printer in a progressively simpler way with less
and less intervening software.	 

Eleminate your word processing application. Manually print a pdf files that you
can view with xpdf.

   View it : xpdf testfile.sxw.pdf ( I made mine in oowriter )
   Print it: lp   testfile.sxw.pdf

   Urrk no improvement!

Eleminate the pdf interpreter. Print text:

   Like this: lp tide.txt

   Wrrk no improvement!

Eleminate the computer.

   Run the printer self-test. Visit the manufacturer's web site for
instructions. For my HP Deskjet 690C:

       Press printer ON/Off button (so printer is off)..
       Hold "page feed" button AND press printer ON/Off button.

The self test printout shows the bad printing!

    Voila: The printer has a dirty printhead or dirty cartridge!

Resolution: Go to the HP.COM/printer/support web site and get cleaning
instructions. With two cotton swabs and two paper towels I clean off gobs of
dust that are smearing the printing.