Squaring the Print Head

If the test pattern, printed on a wide web (4" (100mm) plus), is lighter on one edge than the other, it is possible that the printhead is out of square. This can be detected by looking at the front edge of the print head in reference to the printhead holder. To remedy this problem, power off the machine and remove the print head as outlined in the print head installation information. The printhead adjustment plate has been manufactured so when properly adjusted the head will be square. The printhead holder has a locator plate that must be slide up snug against the printhead mount plate. Install the head and it should be square to the web.

Print Head Tangent Point

The print head pressure adjustment must be done with the head pressure set light. Turn the pressure screw counterclockwise. Run a test pattern to determine the adjustment required.

If the entire test pattern is broken up, the printhead is probably not adjusted to the proper tangent point. To adjust the tangent point loosen the two print head lock screws one half turn with a 2.5mm ball driver provided in your spare parts kit. Do not remove the print head from the printer.

Once the screws have been loosened, use the adjustment thumb screw to move the head forward and backwards. Since the adjustment is very precise, do not turn the thumb screw more than 1/4 of a turn before running another test pattern to determine if you are adjusting the print head in the proper direction. Tighten the two mount screws (Do not over tighten). Run a test pattern again to determine further adjustment required.

Once you have restored a smooth even test pattern, re-tighten the two print head mount screws (Do not over tighten) and run one last test pattern.

Registration Sensor Adjustment

Adjusting Print Sensor Position

If you are running sense mark material with a hole or slot for registration:

-Open the feed roller and print head.

-Move the stock by hand in the feed direction until the registration desired is in the slot window for the pickup sensor.

-Close both the feed and print head.

-Slide the top sensor assembly using the sensor handle while looking at the registration index sensor. When the light turns on, and stays on, the sensor is over the registration hole.

If your machine stops, for no apparent reason, while it is in the middle of printing a batch of tickets, you may be missing sense marks (three consecutive tickets in which a sense mark was not found). Check for the following:

-The front panel will display a screen indicating that there has been a missed sensor error.

Users Manual Model 656/636

Maintenance / Adjustments • 33

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Paxar 656 / 636 user manual Registration Sensor Adjustment, Squaring the Print Head, Print Head Tangent Point