Printronix

P7000 print has wavy vertical lines

Product: P7000

Symptom

P7000 print has wavy vertical lines

Possible Cause

Electronic timing value known as "phasing" could be incorrect.

Recommend Solution

Adjust the printer "phasing" to help create straight vertical lines.You must check and adjust hammer phasing if the controller board is replaced, the shuttle frame assembly is removed, or if the MPU is replaced.

Printing occurs as the shuttle moves horizontally in both directions. A vertical line is plotted by printing a dot as the shuttle moves left-to-right, then advancing paper the height of one dot and putting the next dot beneath the first as the shuttle moves right-toleft.
'Phasing' refers to the delay imposed on the timing of the shuttle's return motion, so that the left-to-right dots and the right-to-left dots line up vertically. The value depends on the electronics in the shuttle, and varies from shuttle to shuttle. If the phasing is not
correct, vertical lines will appear wavy or zig-zagged.


A quick test to see if phasing is an issue is to enable the 'Unidirectional' mode in the PRINTER CONTROL menu. In Unidirectional mode, the printer only prints from one direction, so the phasing value is no longer used. Unidirectional print is approximately one-half normal print speed.

  1. Power on the printer, load paper and set top-of-form. 
  2. If the printer is online, press the ON LINE key to place the printer offline.
    “OFFLINE / QUICK SETUP.” displays. 
  3. On the control panel, press the UP + DOWN keys to unlock the ENTER key.
    “ENTER SWITCH UNLOCKED” briefly displays. (If “LOCKED” displays, simply press UP + DOWN again.
  4. Press the RIGHT key until “OFFLINE / PRINTER CONTROL” displays.
  5. Press DOWN.
  6. Press RIGHT until “PRINTER CONTROL / Unidirectional” displays.
  7. Press DOWN.
  8. Press RIGHT until “Unidirectional / Enable” displays.
  9. Press ENTER.
  10. Press ON LINE twice.
  11. Print a sample job or print a configuration listing, looking at the vertical strokes.

 

If print quality does not improve with Unidirectional, then there is some other issue. But if Unidirectional mode clears up the wavy print, disable Unidirectional and adjust the phasing.

THE PHASE PRINTER TEST

The Phase Printer test is located in the Diagnostics menu. It requires full-width (14 7/8") paper. The test assumes the shuttle is installed correctly, with the proper gap.

Follow the steps below to start and stop the Phase Printer test. There are no specific values for this parameter, but if too large a value is selected, a timing error such as PAP FIFO UNDRFL* may result, and a smaller value must be tried.

NOTE: The printer must be printing the phase pattern of “H’s” when the phasing value is changed, or the new phasing value will not be written into memory. If the value is changed when not printing, the printer will return to its default phasing value when
powered off then back on.


*** PAY ATTENTION TO STEP 9 AND STEP 10. ***

  1. Load full width (14 7/8") paper and set the top of form.
  2. Power on the printer.
  3. If the printer is online, press the ON LINE key to place the printer offline.
    “OFFLINE / QUICK SETUP.” displays.
  4. On the control panel, press the UP + DOWN keys to unlock the ENTER key.
    “ENTER SWITCH UNLOCKED” briefly displays. (If “LOCKED” displays, simply press UP and DOWN again. This is the default key combination. The lock/unlock key combination can be programmed by the user. If UP+ DOWN does not unlock ENTER, get the new key combination from the user.)
  5. Press the RIGHT key until “OFFLINE / DIAGNOSTICS” displays.
  6. Press DOWN. Press RIGHT until “DIAGNOSTICS / Printer Tests” displays. 
  7. Press DOWN.
  8. Press RIGHT until “Printer Tests / Phase Printer” displays.
  9. Press ENTER. The display shows “Printer Tests / Phase Printer” and the test begins.
    The current phasing value is printed on the left of the printed pattern of all H’s.
    If the vertical bars of the H characters are wavy, go to step 10.
    If the H characters look normal, go to step 14.
  10. Press DOWN: The current phase index displays.
    Press DOWN again: An asterisk (*) appears next to the phase value.
  11. Press RIGHT to increase or LEFT to decrease the phasing index value, then press ENTER to activate the value as it prints.
  12. If the vertical bars of the H characters are wavy, go to step 11.
  13. Press UP twice: “Printer Tests / Phase Printer” displays.
  14. Press ENTER to stop the test.
  15. Press CLEAR. “OFFLINE / QUICK SETUP” displays.
  16. Press UP + DOWN (or the key combination set by the user).
    “ENTER SWITCH LOCKED” briefly displays.
  17. Press the ON LINE key to place the printer online.


NOTE: If you changed the phasing value, write the new phase value down and store it with the printer.

A possible testing scenario would be to start at a low phase (20) and test in increments of +20 until the quality improves. Then start a second test just below the point where the print quality improved, with an increment of +5, until the print quality shows improvement. A third pass with an increment of +1 could be taken from that point.