JP 500  (260-2950)          Care and Maintenance       Faxback Doc. # 3642

This printer is designed to require only minimum maintenance.  However,
everyday use will give rise to a number of simple printer - care
operations.

!   If you detect serious mechanical damage to or a failure in the
    printer, do not attempt to repair it yourself!  Take your printer to a
    Radio Shack Repair Center.

Changing the Ink Jet Print Head

If dots or lines are not printed completely, remove the ink jet print head
completely and reinsert it (see the sections entitled "Ink Jet Print Head
Removal" and "Ink Jet Print Head Insertion" in this manual), or execute
the print head cleaning and/or PRIME operations (see the specific sections
in this chapter).

If none of these operations result in improved print quality, you must
replace the print head.

    ALWAYS use manufacturer-original Bubble Ink Jet Print Heads.

PRIME Operation

The PRIME operation is performed to clear the print head nozzles.  If,
after inserting a new print head or during a printing operation, the print
quality is not optimal or deteriorates, execute the PRIME operation to
improve it.  Poor print quality is usually caused by air bubbles which
block one or more of the print head nozzles; the PRIME operation will
clear any blockage.

To clear the  print head nozzles, proceed as follows:

    Make sure that the printer is not operating (the print head is in its
    rest position at the physical left hand margin)

    Press down completely, hold for two to three seconds and then release
    the PRIME button on the top rear left of the printer.  This operation
    should be repeated at least twice

    Press Economy/LQ for at least three seconds; the print head carriage
    will move to the head loading position on its shaft.

    Press the PRIME button and hold it for two to three seconds and then
    release it, four or five times, to empty the ink tube.  Control on the
    transparent portion of the PRIME button that the ink is flowing.
    Press the PRIME button until its transparent portion is free of ink.

    Press any key to return the printer On Line.

If the PRIME operation does not result in improved print quality, or if no
ink flow has been observed, repeat the PRIME operation.

Cleaning the Print Head

If, during alphanumeric printing, horizontal white lines appear across the
characters or other print quality defects occur, and you have not been
able to resolve the problem by replacing the print head or with the PRIME
operation, try removing and cleaning the print head.

    Press the Economy/LQ key for at least three seconds to interrupt
    printing and position the print head carriage in the head loading
    position.

    Open the front cover open.

    Pull the black lip on the front of the print head carriage slightly
    towards you; the print head will be released.

    Holding it by its casing, remove the print head from the printer.

    Clean the electrical contacts on the head and in the head chamber with
    a slightly damp lint-free cloth, taking care not to touch the print
    head nozzles.

    Re-insert the print head in the printer, close the front cover and
    press any key to return the printer ON-LINE.

If there is still no improvement in the print quality, try cleaning the
print head nozzles.

!   This operation MUST NOT be repeated systematically, as it will damage
    the print head.

    It should ONLY be attempted as a last resort, before changing the
    print head.

    Dampen a tissue handkerchief with distilled water; wring it slightly
    to remove any excess water.

    Remove the print head from the printer.

    Holding the print head with the nozzles facing downwards, blot it
    against the handkerchief, pressing lightly.

    Repeat the blotting operation a few times on different areas of the
    handkerchief, to clean the nozzles.

    Reinsert the print head in the printer and run a print test to check
    the quality of printing.

(br/all-12/15/94)