Epson Stylus Color 980 Service Manual page 66

EPSON Stylus Color 980
False firing is detected in the following conditions, and the printer
handles it as described below.
False firing detection timing:
If any of the 5 channels, which are monitored by the abnormal
temperature detection circuit in the nozzle selector, reaches 100
C, the printer stops printing and automatically begins the
cleaning cycle. In this case, the printer runs the most powerful
cleaning cycle. The particular address bit called abnormal
temperature detection flag is reset at this point.
Process after detection:
The printer does not resume printing until the temperature
around the PZT recovers to the tolerable range. In case the
printer detects the same abnormal condition again, it indicates
an ink-end error to urge the user to replace the cartridge
considering the following possible reasons:
1. The currently installed ink cartridge is far beyond its useful
life (6 months). Ink, in this condition, does not eject properly
and results in a false firing. When a new cartridge is
installed, the problem is solved.
2. The cartridge installed has been repeatedly removed and
then installed again several times. With this mis-handling of
the cartridge, the ink consumption counter can not properly
describe the actual remaining ink level, and a false firing
occurs as a result. The solution in this case is also replacing
the ink cartridge with a new one.
Furthermore, If an ink cartridge is removed from the printer,
air comes in and bubbles inside the cartridge. Unlike a new
cartridge, the ink inside the removed cartridges is not
deaerated, so the bubbles inside can not be absorbed into
the ink due to the ink's saturated condition. For this reason,
Operating Principles Electrical Circuit Operation Principles
the more the cartridge is removed/installed, the more
bubbles are formed, and the printhead can not eject ink
properly and false firing occurs.
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