HP Latex 850 Printer - Manual (Page 14)

3 Troubleshooting
If you see an error message numbered 78.2:01, it means that the substrate may have become
detached from the rear spindle, or the core is slipping on the dual roll. This could mean that you have
reached the end of the roll, or the roll is a non-standard size and is too big in diameter, or the dual-roll
differential hub is locked. The substrate is automatically unloaded when this error occurs.
You should respond to this error in the following ways.
● Check whether you have reached the end of a roll.
● For dual-roll printing, check that the differential hub is unlocked.
● Check that the hubs are tightly secured to the spindle.
● Check that the diameter of each substrate core is not too large for the spindle, if it is, move the
rubber ring of the Dual Roll to a larger diameter so that it grips the core tighter.
To check to see if the core is slipping on the dual roll, make a mark on the core and the on the
differential of the dual roll at the same level, and check if the marks separate as the substrate
advances. This type of issue will not trigger an error message, but there will be poor advance
accuracy, which will look like banding.
● Check that each substrate core is tightly connected to the hubs on each side of it.
● If the roll cannot be inserted on to the differential, ensure that the rubber ring is in the smallest
diameter slot.
If the substrate is skewed, check that the hubs are tightly connected to the spindle and to the substrate
core.
If you experience banding or lack of tension in the substrate, check that the differential hub is unlocked
and tightly connected to the spindle. Lack of tension can also occur when successive layers of substrate
stick to each other on the roll.
If you experience ink smears on the substrate after a period of dual-roll printing, try removing the
central edge holders.
10 Chapter 3 Troubleshooting ENWW
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